Lunar exploration is the study of the Earth's satellite using spacecraft and optical instruments.

Initially, the only method for humanity to study the Moon was the visual method. Galileo's invention of the telescope in 1609 allowed significant progress in the study of the Moon using optical instruments. Galileo himself used his telescope to study the mountains and craters on the lunar surface. Research on the Earth's satellite using spacecraft began on September 13, 1959, with the landing of the Soviet automatic station Luna-2 on the surface of the satellite. In 1969, a man landed on the Moon, and the study of the satellite from its surface began.

Currently, several space powers have plans to resume manned flights to the lunar surface and create lunar bases.

Antiquity and the Middle Ages

The moon has attracted the attention of people since ancient times. In the II century. BC e. Hipparchus studied the movement of the Moon across the starry sky, determining the inclination of the lunar orbit relative to the ecliptic, the size of the Moon and its distance from the Earth, and also identified a number of features of the movement.

The theory obtained by Hipparchus was subsequently developed by the astronomer from Alexandria Claudius Ptolemy in the 2nd century AD. e., writing the book “Almagest” about it. This theory was refined many times, and in 1687, after Newton’s discovery of the law of universal gravitation, from a purely kinematic one, describing the geometric properties of motion, the theory became dynamic, taking into account the motion of bodies under the influence of forces applied to them.

The invention of telescopes made it possible to distinguish finer details of the lunar relief. One of the first lunar maps was compiled by Giovanni Riccioli in 1651, he also gave names to large dark areas, calling them “seas,” which we still use today. These place names reflected the long-standing idea that the weather on the Moon was similar to that on Earth, and the dark areas were supposedly filled with lunar water, and the light areas were considered dry land. However, in 1753, Croatian astronomer Ruđer Bošković proved that the Moon does not have an atmosphere. The fact is that when stars are covered by the Moon, they disappear instantly. But if the Moon had an atmosphere, the stars would fade out gradually. This indicated that the satellite had no atmosphere. And in this case, there cannot be liquid water on the surface of the Moon, since it would instantly evaporate.

With the light hand of the same Giovanni Riccioli, craters began to be given the names of famous scientists: from Plato, Aristotle and Archimedes to Vernadsky, Tsiolkovsky and Pavlov.

XX century

Since the beginning of the space age, our knowledge of the Moon has increased significantly. The composition of the lunar soil became known, scientists received its samples, and a map of the reverse side was compiled.

The Moon was first reached by the Soviet automatic interplanetary station Luna-2 on September 13, 1959. The first glimpse of the far side of the Moon was possible in 1959, when the Soviet probe Luna 3 flew over it and photographed a part of its surface invisible from Earth. Optical telescopes placed here would not have to break through the dense earth's atmosphere. And for radio telescopes, the Moon would serve as a natural shield of solid rocks 3,500 km thick, which would reliably cover them from any radio interference from the Earth. The world's first soft landing on the Moon took place on February 3, 1966, by the Soviet space probe Luna 9, which also transmitted images of the surface of another celestial body for the first time.

In the early 1960s, it was obvious that the United States was lagging behind the USSR in space exploration. J. Kennedy said that a man would land on the Moon before 1970. To prepare for a manned flight, NASA completed several AMS programs: Ranger (1961-1965, surface photography), Surveyor (1966-1968, soft landing and terrain surveys) and Lunar Orbiter (1966-1967, detailed surface imaging Moon). Also in 1965-1966 there was a NASA project MOON-BLINK to study unusual phenomena (anomalies) on the surface of the Moon. Work was performed by Trident Engineering Associates (Annapolis, Maryland) under contract NAS 5-9613 dated June 1, 1965 from Goddard Space Flight Center (Greenbelt, Maryland).

The successful American manned mission to the Moon was called Apollo. The world's first flyby of the Moon took place in December 1968 on the manned Apollo 8 spacecraft. After a rehearsal flight in May 1969 to the Moon without Apollo 10 landing on it, the world's first lunar landing took place on July 20, 1969 on Apollo 11 (the first person to set foot on the lunar surface on July 21 was Neil Armstrong, the second - Edwin Aldrin; third crew member Michael Collins remained in the orbital module); the last sixth - in December 1972. Thus, the Moon is the only celestial body visited by man, and the first celestial body whose samples were delivered to Earth (the USA delivered 380 kilograms, the USSR - 324 grams of lunar soil).

During the emergency flight of Apollo 13, there was no landing on the moon. During the last three flights of the program, lunar electric vehicles controlled by landing astronauts were used. Three additional flights under the program (Apollo 18...20), which were in a high degree of readiness, were cancelled. There are conspiracy theories about the so-called. “lunar conspiracy”, that the landings on the Moon were only staged, but were not actually carried out, or that the above was deliberate disinformation, and the Apollo program was curtailed due to the discovery of an alien presence on the Moon.

Due to the emerging gap from the United States, two Soviet lunar manned programs - lunar flyby L1 and lunar landing L3 - were terminated at the stage of testing unmanned flights of spacecraft without achieving the target result. Also, the world’s first detailed project of the lunar base “Zvezda”, developed as a development of the L3 program, and the proposed subsequent projects of the lunar expeditions L3M and LEK were not implemented. Among the numerous lunar landing and lunar orbital stations “Luna”, the USSR provided automatic delivery to Earth of lunar soil samples on the Luna-16, Luna-20, Luna-24 AMS and carried out research on the lunar surface also using two radio-controlled self-propelled vehicles - Lunokhods, Lunokhod-1, launched to the Moon in November 1970 and Lunokhod-2 - in January 1973. Lunokhod-1 operated for 10.5 Earth months, Lunokhod-2 - 4.5 Earth months ( that is, 5 lunar days and 4 lunar nights). Both devices collected and transmitted to Earth a large amount of data about the lunar soil and many photographs of details and panoramas of the lunar relief.

After the last Soviet station Luna-24 delivered lunar soil samples to Earth in August 1976, the next device, the Japanese Hiten satellite, flew to the Moon only in 1990. Then two American spacecraft were launched - Clementine in 1994 and Lunar Prospector in 1998.

XXI Century

After the end of the Soviet space program “Luna” and the American “Apollo”, exploration of the Moon using spacecraft was practically stopped. But at the beginning of the 21st century, China published its program for the exploration of the Moon, which included, after delivering the lunar rover and sending soil to Earth, then expeditions to the Moon and the construction of inhabited lunar bases. This is believed to have caused the remaining space powers to re-launch lunar programs as a new "lunar race for second place." Plans for future lunar expeditions were announced by Russia, Europe, India, Japan, and President George W. Bush announced on January 14, 2004 that the United States was beginning a large-scale detailed Constellation program with the creation of new launch vehicles and manned spacecraft capable of delivering to the Moon of people and large manned lunar rovers, with the aim of establishing the first lunar bases. The Constellation Lunar program was canceled after 5 years by President Barack Obama.

On September 28, 2003, the European Space Agency launched its first automatic interplanetary station (AMS), Smart-1. On September 14, 2007, Japan launched its second lunar exploration station, Kaguya. And on October 24, 2007, the PRC also entered the lunar race - the first Chinese lunar satellite, Chang'e-1, was launched. With the help of this and the next stations, scientists are creating a three-dimensional map of the lunar surface, which in the future may contribute to an ambitious project of colonization of the Moon. On October 22, 2008, the first Indian satellite, Chandrayaan-1, was launched. In 2010, China launched the second AMS Chang'e-2.

Apollo 17 landing site. Visible are the descent module, ALSEP research equipment, car wheel tracks and foot tracks of astronauts.

On June 18, 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS). The satellites are designed to collect information about the lunar surface, search for water and suitable locations for future lunar expeditions. On the occasion of the fortieth anniversary of the Apollo 11 flight, the automatic interplanetary station LRO completed a special task - it photographed the landing areas of lunar modules of earthly expeditions. Between July 11 and July 15, LRO took and transmitted to Earth the first-ever detailed orbital images of the lunar modules themselves, landing sites, pieces of equipment left behind by expeditions on the surface, and even traces of the cart, rover, and earthlings themselves. During this time, 5 of the 6 landing sites were photographed: expeditions Apollo 11, 14, 15, 16, 17. Later, the LRO spacecraft took even more detailed photographs of the surface, where not only the landing modules and equipment with traces of the lunar vehicle are clearly visible, but also walking tracks of the astronauts themselves. On October 9, 2009, the LCROSS spacecraft and the Centaurus upper stage made a planned fall onto the lunar surface into the Cabeus crater, located approximately 100 km from the lunar south pole, and therefore constantly located in deep shadow. On November 13, NASA announced that water had been discovered on the Moon using this experiment.

Private companies are starting to explore the Moon. The global Google Lunar X PRIZE competition was announced to create a small lunar rover, in which several teams from different countries are participating, including the Russian Selenokhod. In 2014, the first private lunar flyby AMS (Manfred Memorial Moon Mission) appeared. There are plans to organize space tourism with flights around the Moon on Russian ships - first on the modernized Soyuz, and then on the promising universal PTK NP (Rus) being developed.

The United States is going to continue exploration of the Moon with automatic stations GRAIL (launched in 2011), LADEE (launched in 2013) and others. China launched its first lunar lander, Chang'e 3, with the first lunar rover in December 2013 and its first lunar flyby with a return vehicle in 2014, and is further planning a lunar soil return vehicle by 2017 in anticipation of manned flights around 2025 and construction of a lunar base by 2050, Japan announced future robotic exploration of the Moon. India is planning a 2017 mission of its Chandrayaan-2 orbiter and a small rover delivered by the Russian Luna-Resurs spacecraft, and further exploration of the Moon up to manned expeditions. Russia first launches a multi-stage program for exploring the Moon with automatic stations “Luna-Glob” in 2015, “Luna-Resurs-2” and “Luna-Resurs-3” with lunar rovers in 2020 and 2022, “Luna-Resurs-4” upon return soil collected by lunar rovers in 2023, and then plans manned expeditions in the 2030s.

It is possible that the Moon may contain not only silver, mercury and alcohols, but also other chemical elements and compounds. Water ice, molecular hydrogen found by the LCROSS and LRO missions in the lunar crater Cabeus indicate that the Moon does have resources that could be used by future missions. Analysis of topographic data sent by the LRO spacecraft and Kaguya gravitational measurements showed that the thickness of the crust on the far side of the Moon is not constant and varies with latitude. The thickest sections of the crust correspond to the highest elevations, which is also typical for the Earth, and the thinnest are found in subpolar latitudes.

Conclusion

The 47 years that have passed since the first spacecraft landed on the Moon have brought science many new and sometimes unexpected things. Scientists - astronomers, geologists, geophysicists, geochemists - are now summing up the results of intense lunar expeditions. Having been steadily moving away from the Earth for billions of years, in recent years the Moon has become closer and more understandable to people. One can agree with the apt remark of one of the prominent selenologists: “from an astronomical object, the Moon has turned into a geophysical one.”

The curtain was lifted on the secrets of the early youth of the Moon, the Earth and, apparently, all the planets of the terrestrial group, and at the same time the outline of their distant future was outlined. Much has become clearer, but much remains hidden in the “fog” of ambiguity - after all, there is still little data, and discoveries, as often happens, have given rise to many new questions.

Selenologists have no doubt that the activity of the Moon, both magmatic and tectonic, was short and related only to the early stages of its evolution, but there is still heated debate about the cosmic “overture” - the origin of the Moon. The chronology of the emergence of the lunar seas has been reliably reconstructed, but the nature of the mascons “buried” in them is unclear. It turned out that a long-lasting “seismic ringing” is generated in the upper inhomogeneous layers of the Moon, but the disappearance of transverse waves in the middle of the lunar radius remains a mystery. No magnetic dipole has been discovered on the Moon, but the high remanent magnetization of lunar rocks indicates that one existed a long time ago.

In many of their basic characteristics, the Earth and the Moon are similar and, apparently, are “cosmic relatives.” This primarily concerns their formation and the initial stage of evolution, the similar chemical composition of these celestial bodies and the layered structure of their interiors. However, in many ways this “kinship” turned out to be very distant. The Earth is full of “tectonic storms”, the Moon is passive and non-seismic. The “tectonic life” of the Earth and even the nature of its surface are largely determined by internal reasons, while on the Moon they are mainly of external - cosmic - origin.

Various stages of the “planetary life” of the Earth left on it new forms of fauna and flora, new mountain ranges, cracks, drifting continents, and earthquake cataclysms. The chronology of the evolution of the Moon is associated with meteorite impacts and, in addition, is limited to the first 1.5 billion years, and since that time tectonic “calm” has been established on the Moon.

Do earthlings really need to explore the Moon? Have they not spent their efforts in vain on space flights unprecedented in the history of mankind - after all, it is clearly unprofitable to develop lunar “mineral resources”? No, not in vain! The Moon rewarded inquisitive and brave astronauts and organizers of space flights, and with them all the people of the Earth. Through the “cratered, dusty lunar window” many earthly problems became clearer. For example, the oldest “stone” in the solar system was found and its age was determined. The pages of the “pre-geological” history of the Earth have been slightly opened, since the surface of the Moon, untouched by winds and waters, demonstrates the appearance of the most ancient relief of the Earth.

The Moon is an ideal model for studying the role of cosmic factors in planetotectonics. Knowledge of the patterns of tidal moonquakes will help to carry out seismic prediction of earthquakes. Based on lunar data, geophysical observation methods and models for their interpretation can be improved.

The study of the structure of the Moon continues - the pendulums of seismometers tremble sensitively, and under the microscopes of scientists there are soil samples from the southern outskirts of the Sea of ​​Crisis, delivered by Luna-24. The joint analysis of the Earth and the Moon lays the foundations for a new stage in comparative planetology. Current and future flights of spacecraft to the terrestrial planets should complement and clarify the patterns concerning the origin, internal structure and evolution of the planets and their satellites.

Bibliography:

1) “Planet Earth. Encyclopedia". Fiona Watt, Felicity Brooks, Richard Spurgeon;

2) textbook “Astronomy 11th grade” by N.P. Prishlyak;

3) https://ru.wikipedia.org/wiki/%D0%97%D0%B5%D0%BC%D0%BB%D1%8F;

4) http://schools.keldysh.ru/school1413/astronom/NikLSite/luna/fizich.htm;

5) http://www.krugosvet.ru/node/36284 ;

>> Exploration of the Moon

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Consider scientific space lunar exploration– Earth’s satellite: the first flight to the Moon and the first man, description of research by devices with photos, important dates.

The Moon is located closest to the Earth, therefore it has become the main object of space exploration and one of the goals of the race between the USA and the USSR. The first devices were launched in the 1950s. and these were primitive mechanisms. But technology did not stand still, which led to Neil Armstrong’s first step on the lunar surface.

In 1959, the Soviet Luna-1 spacecraft was sent to the satellite, flying past at a distance of 3,725 km. This mission is important because it showed that Earth's neighbor lacks a magnetic field.

First moon landing

That same year, Luna 2 was sent, which landed on the surface and recorded several craters. The first blurry photos of the Moon arrived with the third mission. In 1962, the first American probe, Ranger 4, arrived. But it was a suicide bomber. Scientists specifically sent it to the surface to get more data.

Ranger 7 departed 2 years later and transmitted 4,000 images before its death. In 1966, Luna 9 landed safely on the surface. Scientific instruments not only sent back better images, but also studied the features of the alien world.

Successful American missions were the Surveyor (1966-1968), which explored the soil and landscape. Also in 1966-1967. American probes were sent and settled in orbit. This way we managed to fix 99% of the surface. This was the period of exploration of the Moon by spacecraft. Having obtained a sufficient database, it was time to send the first man to the Moon.

Man on the Moon

On July 20, 1969, the first people arrived at the satellite - Neil Armstrong and Buzz Aldrin, after which American exploration of the Moon began. The Apollo 11 mission landed in the Sea of ​​Tranquility. Later, a lunar rover will arrive, which will allow us to move faster. Until 1972, 5 missions and 12 people managed to arrive. Conspiracy theorists are still trying to figure out whether Americans were on the moon by providing the latest research and scrutinizing videos. There is no exact refutation of the flight yet, so we will consider Neil Armstrong’s first step as a breakthrough in space research.

This breakthrough allowed us to focus on other objects. But in 1994, NASA returned to the lunar theme. The Clementine mission was able to image the surface layer at different wavelengths. Since 1999, Lunar Prospector has been searching for ice.

Today, interest in the celestial body is returning and new space exploration of the Moon is being prepared. In addition to America, India, China, Japan and Russia are also looking at the satellite. There is already talk of colonies, and people will be able to return to Earth's satellite in the 2020s. Below you can see a list of spacecraft sent to the Moon and significant dates.

Significant dates:

• 1609– Thomas Harriot became the first to point a telescope into the sky and image the Moon. Later he would create the first maps;
• 1610– Galileo issues a publication of observations of the satellite (Star Herald);
• 1959-1976– The US lunar program of 17 robotic missions reached the surface and returned samples three times;
• 1961-1968– American launches prepare the way for the launch of the first people to the Moon as part of the Apollo program;
• 1969– Neil Armstrong became the first person to set foot on the lunar surface;
• 1994-1999– Clementine and Lunar Reconnaissance transmit data about the possibility of water ice at the poles;
• 2003– SMART-1 from ESA produces data on the main lunar chemical constituents;
• 2007-2008– The Japanese Kaguya spacecraft and the Chinese Shanye-1 launch one-year orbital missions. They will be followed by the Indian Shandrayaan-1;
• 2008– The NASA Lunar Science Institute is formed to lead all lunar exploration missions;
• 2009– NASA's LRO and LCROSS launch together to recapture the satellite. In October, a second device was placed over the shadowed side near the south pole, which helped find water ice;
• 2011– Sending the CRAIL spacecraft to image the inner lunar part (from the crust to the core). NASA launches ARTEMIS, focused on surface composition;
• 2013– NASA's LADEE probe is being sent to collect information about the structure and composition of the thin lunar atmospheric layer. The mission ended in April 2014;
• December 14, 2013– China became the third country to lower the device onto the surface of the satellite – Utah;

Less than a year and a half passed from the launch of the first Earth satellite to the start of exploration of the Moon by spacecraft. And this is not surprising since the Moon is the closest object to the Earth and a very unusual object for the Solar System: the Earth/Moon mass ratio exceeds all other planetary satellites and is 81/1 - the closest such indicator is only 4226/1 for the Saturn cluster /Titanium.

Due to the fact that volcanic activity on the Moon quickly disappeared (due to its relatively small mass), its surface is very ancient and is estimated at almost 4.5 billion years, and the absence of an atmosphere leads to the accumulation on the surface of meteorites whose age and composition can reach and even exceed the age of the solar system itself. All this, in addition to the proximity of the Moon to us, aroused active scientific interest among people and a desire to explore it: the total number of spacecraft sent to study it (including failed missions) already exceeds 90 pieces. And it is about all their diversity that we will talk today.

First steps

The first explorations of the Moon started out rather poorly in both the USSR and the USA: only the fourth of a series of vehicles launched to the Moon (Luna-1 and Pioneer-3, respectively) were even partially successful. This was not surprising since lunar exploration started at a time when both they and we had a couple of successful satellite launches to their credit, so very little was known about the conditions of outer space. Add to this the limited technical difficulties that at that time did not allow spacecraft to be stuffed with heaps of sensors as can be done now (so one could sometimes only guess about the causes of the accident) - and one can imagine the conditions under which spacecraft designers sometimes had to work.

Discussion of the failure of the Luna-8 station from the book “Korolev: Facts and Myths” by Y. K. Golovanov, a journalist who almost became an astronaut:

The first artificial satellite of the Earth (left), and the Luna-1 station (right)

The same spherical shape, the same four antennas... but in fact there was little in common between the two satellites: Sputnik 1 only had a radio transmitter, while Luna 1 already had several scientific instruments installed. With their help, it was first established that the Moon does not have a magnetic field and the solar wind was recorded for the first time. Also during its flight, an experiment was carried out to create an artificial comet: at a distance of about 120 thousand km from Earth, a cloud of sodium vapor weighing about 1 kg was released from the station, which was recorded as an object of 6th magnitude.

The Luna-1 station is assembled with block “E” - the third stage of the Vostok-L launch vehicle, with the help of which the Luna-2 and Luna-3 stations were also launched.

Film dedicated to the Luna-1 station

Initially, Luna-1 was supposed to be crashed onto its surface, but during the preparation of the flight the delay of the signal from the MCC to the device was not taken into account (at that time radio command control from the ground was used) and the engines fired a little later than necessary led to a miss of 6 thousand km - which Well, “rocket science” has never been a simple matter...

On March 3, 1959, the American apparatus Pioneer-4 was sent along the same flight path with a set of second cosmic speed. His goal was to study the Moon from the flyby trajectory, but a miss of as much as 60 thousand km led to the fact that the photoelectric sensor could not detect the Moon and photographing it failed, however, the Geiger counter established that the lunar environs did not differ in the level of radiation from the interplanetary medium.

Assembly of the Pioneer-3 apparatus - a complete analogue of the Pioneer-4

On September 12, 1959, the Luna-2 station was launched. In addition to hitting the Moon, she was given an additional task - to deliver the USSR pennant to the Moon. At that time, the orientation and orbit correction systems were not yet ready, so the impact was expected to be serious - with a speed of more than 3 km/s. The developers of the device used two technical tricks: 1) the pennants were placed on the surface of two balls with a diameter of about 10 and 15 cm:

When “touching” the Moon, the explosive charge inside these balls detonated, which allowed some of the pennants to reduce their speed relative to the Moon.

2) Another solution involved the use of aluminum tape 25 cm long on which inscriptions were applied. The tape itself was placed in a durable housing filled with liquid with a density similar to that of the tape, and this housing, in turn, was placed in a less durable one. At the moment of impact, the outer casing was crushed and absorbed the impact energy. The liquid served as an additional shock absorber and made it possible to be confident in the safety of the tape. This entire structure was placed on the third stage of the rocket, which put the station on a flight path to the Moon. The fact that the station and the last stage hit the Moon was recorded, but nothing is known about how well the pennants were preserved. Perhaps in the future an expedition of astronautics historians will be able to answer this question.

By October 7, 1959, the first photographs of the far side of the Moon were obtained using the Luna-3 station, which launched on October 4, like all other missions of the Luna program, from Baikonur. It weighed 287 kilograms and was already equipped with a full-fledged orientation system for the Sun and Moon, providing an accuracy of 0.5 degrees when shooting. The station used gravity assist for the first time:

The flight trajectory of the Luna-3 station - this trajectory was calculated under the leadership of Keldysh in order to ensure that the station would fly over the territory of the USSR when it returned to Earth. The next gravity assist maneuver will be performed only by Mariner 10, flying near Venus on February 5, 1974.

The method by which the shooting was carried out was interesting: first, the pictures were taken using photographic equipment, then the film was developed and digitized using a traveling beam camera, after which it was transmitted to Earth. To avoid the risk of the device breaking down before returning to Earth (the flight to the Moon and back took more than a week), two communication modes were provided: slow (when the device was near the Moon, far from the receiving station) and fast (for communication when the device was flying over over the USSR). The decision to duplicate the communication systems turned out to be absolutely correct - the station was able to transmit only 17 of the 29 pictures it took, after which the connection with it was interrupted and it was no longer possible to restore it.

The world's first photograph of the far side of the Moon. The photo was of mediocre quality due to signal transmission interference. But subsequent photos were much better:

As a result, using these 17 images, we were able to construct a fairly detailed map:

High-resolution photographs of the visible side of the Moon were taken by Ranger 7, launched on July 28, 1964. Since this was the only purpose of this device, as many as 6 television cameras were installed on board, which managed to transmit 4,300 images of the Moon in the last 17 minutes of flight before the collision .

The process of approaching the Moon (video accelerated)

The shooting was carried out right up to the collision, but due to the high speed of the station relative to the Moon, the last image was taken from a height of approximately 488 meters and was not fully transmitted:

Ranger 8 and Ranger 9 were launched for exactly the same purpose (February 17 and March 21, 1965, respectively).

Better images of the far side of the Moon were obtained by the Zond-3 station launched on July 18, 1965. Initially, this station was prepared together with Probe 2 for a flight to Mars, but due to problems, the launch window was missed and Probe 3 went around the Moon. To test the new communication system, photographs received by the station were transmitted to Earth several times.

Photo taken by Zond-3

Soft landing and soil delivery

The task of a soft landing on the Moon was much more difficult and was only accomplished on February 3, 1966 by the Luna-9 station, launched on January 31. The device had a rather complex design:

Due to the fact that nothing was known about the surface of the Moon, the landing process was quite intricate:

The complexity of the landing system did not go unnoticed: from the landing station of 1.5 tons, there remained an ALS weighing only 100 kg, which on the surface looked something like this:

Since the illumination on the Moon changes extremely slowly (the Moon rotates only 1° relative to the Sun in 2 hours), it was decided to use an optical-mechanical imaging system that was much more reliable, lighter and consumed less energy. Its slow operating speed turned out to be even a positive factor - a slow communication channel was sufficient for data transmission, so the ALS could get by with omnidirectional antennas.

The first photograph of the lunar surface was a circular panorama with a resolution of 500 by 6000 pixels; it took 100 minutes to take one photograph. The television camera had a viewing angle of 29° vertically, in addition to which the design of the device provided for its inclination by 16° relative to the vertical of the area - so that it could capture both a distant panorama and nearby surface microrelief:

Click on the full panorama of the Moon. Additional photographs of the station's structure can be seen, and the camera itself filming looked like this:

At the moment, enthusiasts from NASA are going to look for the flight block and the remains of the station's inflatable shock absorber using photographs of LRO (the device itself is too small to be seen - in LRO photographs it should look like 2 * 2 pixels).

The Americans managed to land the Surveyor-1 lander by June 2 (4 months after our station). There were many sensors installed on it:

The device itself carried out landing from the flight trajectory, so instruments for this purpose were installed on it: the main engine (dropped at an altitude of 10 km), steering engines and an altimeter/speed sensor. The landing supports were made of aluminum honeycomb to soften the impact during landing. Among the target equipment of the devices were a television camera, a sensor for analyzing light reflected from the surface (to determine the chemical composition of the soil) and sensors for determining surface temperature. Starting from the third apparatus, a sampler was also installed with which trenches were made to determine the properties of the soil. Of the 7 Surveyors sent to the Moon before February 1968, two crashed while braking near the Moon, and the remaining 5 landed and completed their tasks to explore the Moon.

On March 31, 1966, the Luna-10 station was launched, which by April 3, for the first time in history, entered the orbit of our satellite. It had a gamma spectrometer, a magnetometer, a meteorite detector, and an instrument for studying the solar wind and infrared radiation of the Moon. Studies of gravitational anomalies of the Moon (mascons) were also carried out. The total duration of the mission was about 3 months. For the same purpose, the Luna-11 and Luna-12 stations were launched (August 24 and October 22, respectively).

General view of the station with the transfer stage and its design. This transfer stage was also used in stations from Luna-4 to Luna-9 inclusive.

Since August 10, 1966, five devices of the Lunar Orbiter series have been sent to the Moon. Like Soviet stations, they used photographic film for filming. Since they were launched already as part of the preparation of the Apollo program, cartography of the Moon primarily included photographs of future landing sites for the Lunar Modules. Their operation time was less than two weeks, the images had a resolution of up to 20 meters and covered 99% of the entire lunar surface, and images were taken for 36 potential landing sites with a resolution of 2 meters.

The device itself was quite large: with a total structure weight of only 385.6 kg, the span of the solar panels was 3.72 meters, and the directional antenna was 1.32 meters in diameter. The photographic equipment had two lenses for simultaneous wide-angle and high-resolution shots. This system was developed by Kodak based on the optical reconnaissance systems of the U-2 and SR-71 aircraft.

Additionally, they had micrometeorite detectors and a radio beacon to measure gravitational conditions near the Moon (with which mascons were also spotted). They threatened the safety of the astronauts, since a landing without taking them into account according to the calculations could lead to a deviation of 2 km instead of the standard 200 m. A painstaking study of the orbits of the devices made it possible to measure the influence of the mascons and increase the accuracy of the landing - Apollo 12 was already able to land with a deviation of only 163 meters from your goal.

On July 19, 1967, in parallel with the Surveyor and Lunar Orbiter programs, Explorer-35 was launched, which operated in lunar orbit for 6 years - until June 24, 1973. The device was intended to study the magnetic field, the composition of the surface layers of the Moon (based on the reflected electromagnetic signal), register ionizing particles, measure the characteristics of micrometeorites (by speed, direction and rotational moment) and also study the solar wind.

The next Soviet spacecraft aimed at the Moon was Zond 5, launched on September 15, 1968. The device was a Soyuz 7K-L1 spacecraft launched by a Proton launch vehicle and was intended to fly around the Moon. In addition to testing the ship itself, it also had a scientific purpose: it carried the first living creatures to fly around the Moon 3 months before Apollo 8 - these were two turtles, fruit flies, and several species of plants. After flying around the Moon, the descent module splashed down in the waters of the Indian Ocean:

Apart from problems with overloads during landing, the flight went well, so the next probe, Zond-6 (launched on November 10, 1968), landed not in the sea, but in the regular landing area on the territory of the USSR. Unfortunately, he suffered an accident during the parachute descent stage: they were shot at an altitude of about 5 km instead of the calculated moment right before touching the ground, and all biological objects on board (which were sent to fly around the Moon in this flight) died. However, film with black and white and color photographs of the Moon has been preserved.

Two more successful launches of this spacecraft were made: Zond 7 and Zond 8 (August 8, 1969 and October 20, 1970, respectively) with successful returns of the descent vehicles.

On July 13, 1969 (three days before the launch of Apollo 11), the Luna 15 station was launched, which was supposed to deliver samples of lunar soil to Earth before the Americans had time to do so. However, during the braking process, Luna lost contact with her. As a result, the first automatic station to deliver samples of lunar soil was Luna-16, launched on September 12, 1970:

On September 20, the 1,880-kilogram lander reached the lunar surface. The sample was obtained using a drill, which within 7 minutes reached 35 cm in depth and removed 101 grams of lunar soil. Then the return vehicle, weighing 512 kg, was launched from the Moon, and already on September 24, samples on a 35-kilogram descent vehicle landed on the territory of Kazakhstan.

Also, for the purpose of delivering lunar soil, the Luna-20 and Luna 24 stations were sent (launched on February 14, 1972 and August 9, 1976, delivering 30 and 170 grams of soil, respectively). Luna 24 managed to obtain soil samples from a depth of 1.6 m. A small portion of lunar soil was transferred to NASA in December 1976. The Luna-24 station became the last spacecraft for the next 37 years to perform a soft landing on the Moon - until the landing of the Chinese “Jade Hare”.

Lunokhods and the final stage of the first stage of research

Launched on November 10, 1970, the Luna-17 station delivered the world's first planetary rover: Lunokhod-1, which operated on the surface for 301 days. It was equipped with two television cameras, 4 telephotometers, an X-ray spectrometer and an X-ray telescope, an odometer-penetrometer, a radiation detector and a laser reflector.

During his work, he traveled more than 10 km, transmitted about 25 thousand photographs to the ground, 537 measurements were made of the physical and mechanical properties of lunar soil, and 25 times - chemical ones.

Lunokhod remote control

On January 8, 1973, Lunokhod-2 was launched, which had the same design. Despite the breakdown of the navigation system, he managed to travel more than 42 km, which was a record for planetary rovers until 2015, when this record was broken by the Opportunity rover. The flight of Lunokhod-3, planned for 1977, was unfortunately cancelled.

Photos of Lunokhod-3 in the museum of the NPO named after S. A. Lavochkin

On October 3, 1971, the automatic interplanetary station Luna-19 was launched into lunar orbit by the Proton-K rocket, which operated for 388 days. Its weight was 5.6 tons and it was built on the basis of the design of the previous Luna-17 station:

The scientific equipment included a dosimeter, a radiometric laboratory, a magnetometer mounted on a 2-meter rod, equipment for determining the density of meteorite matter, as well as cameras for photographing the lunar surface. One of the main tasks of the apparatus was the study of mascons. Due to the failure of the control system and entering an incorrect orbit, it was decided to abandon the task of cartography of the Moon. During the flight, additional data was obtained on the magnetic field of the Moon and it was found that the density of meteorite particles near the Moon does not differ from their concentration in the range of 0.8-1.2 AU. from the sun.

On May 29, 1974, the Luna-22 station was launched with the same scientific program; the station operated for 521 days. These stations made it possible to clarify the gravitational fields of the Moon, and to simplify the landing of the Luna-20 and Luna-24 stations for soil sampling.

Solar system and AWS

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The first spacecraft for studying the Moon and cislunar space was launched in the USSR (1959). On October 7, 1959, the Soviet Luna-3 apparatus transmitted to Earth the first images of the far side of the Moon, which had never been seen by man. Subsequently, according to the Soviet space program, a soft landing on the lunar surface was carried out for the first time, an artificial lunar satellite was created; The spacecraft returned to Earth at the second escape velocity after flying around the Moon, self-propelled vehicles - “Lunokhovers” - were delivered to the lunar surface, and samples of lunar soil were delivered to Earth.

The sixties will long be remembered as a decade marked by one of the greatest technological achievements of mankind in the entire history of its existence. After a series of successful explorations of the Moon using automatic stations, on July 20, 1969, a person first set foot on the lunar surface.

The original goal of the American lunar exploration program was to obtain at least some information about the Moon. That was the Ranger program. Each Ranger series spacecraft was equipped with six television cameras designed to transmit images of the lunar landscape right up to the moment when the vehicle crashed upon falling onto the lunar surface. The first six launches of the Ranger vehicles ended in failure. However, by 1964, the problems were completely eliminated, and all people on our planet had the opportunity to see “live” television images from the Moon. Between July 1964 and March 1965, the three Ranger spacecraft sent to the Moon transmitted over 17,000 photographs of the lunar surface. The latest images were taken from a height of approximately 500 m, and they show rocks and craters only 1 m across (Fig. 1).

The next important stage in American lunar exploration was marked by the simultaneous implementation of two programs: Surveyor and Orbiter. From May 1966 to January 1968, five Surveyor series spacecraft successfully soft-landed on the lunar surface. Each of these tripods was equipped with a television camera, a manipulator with a bucket, and instruments for studying lunar soil. The successful landings of the Surveyors (some experts were primarily afraid that the devices would have to plunge into a three-meter layer of dust) created confidence in the possible implementation of a space program using manned spacecraft.

While five Surveyors were soft-landed on the lunar surface, five Orbiter series vehicles were launched into orbit around the Moon for extensive photography. All five Orbiter launches were successfully carried out within a year - from August 1966 to August 1967. They transmitted a total of 1950 beautiful large-scale photographs to Earth, covering the entire side of the Moon visible from Earth and 99.5% of the far side. Then scientists first learned that there are no seas on the far side of the Moon. It turned out that there are a huge number of craters there (Fig. 2).

The Surveyor flights showed that spacecraft can land safely on the lunar surface. And the photographs obtained by the Orbiters helped scientists choose a landing site for the first manned lunar lander. This paved the way for the Apollo program.

Between December 1968 and December 1972, 24 people traveled to the Moon (three of them twice). Twelve of these astronauts actually walked on the surface of the Moon. The Apollo program included a wide range of geological research, but its main achievement was the delivery of approximately 360 kg of lunar rocks to Earth.

Analysis of samples returned by the Apollo expeditions showed that there are three types of lunar rocks, each of which contains important information about the nature and evolution of the Moon. First of all, this is anorthosite rock (see Fig. 3) - the type of rock most common throughout the Moon. It is characterized by a high content of feldspar. The second important type of lunar rocks is “creep” norites (KREEP). They are named so because of their high content of potassium (K), rare earth elements (REE) and phosphorus (P). Crip Norites are usually found in the light mountainous regions of the Moon. The dark lunar seas are covered with mare basalts.

Anorthosite rock is the most abundant: it is the oldest type of rock found on the Moon. Data obtained from seismometers (left by astronauts on the surface of the Moon), as well as the results of geochemical analyzes carried out at a distance using instruments mounted on satellites, show that the lunar crust to a depth of 60 km consists predominantly of anorthositic rocks. Among the three main lunar rocks, anorthosite has the highest melting point. Therefore, when the original molten surface of the Moon began to cool, the anorthosite rock solidified first.

Before the Apollo program, there were three competing theories about the origin of the Moon. Some scientists believed that the Moon could have simply been captured by the Earth at one time. Others believed that the primordial Earth could have split into two parts (it was assumed that the Pacific Ocean was a “hole” left after the Moon “broke out” of the Earth). But analysis of lunar rocks appears to support the third hypothesis: that the Moon was formed by the aggregation of tiny rocks that orbited the Earth 4.5 billion years ago, the accretion of particles under the influence of gravitational forces acting near the Earth was to some extent a kind of reduced version of the accretion process that occurred in the primordial solar nebula and led to the birth of planets.

The “birth” of the Moon occurred very quickly - perhaps in just a few thousand years. When the millions and millions of rocks orbiting the Earth hit the ever-increasing Moon with force, its surface must have been a sea of ​​white-hot lava. But once most of the rocks were swept away by the Moon as it moved around the Sun, the lunar surface could begin to cool and harden. This was the same time, 4.5 billion years ago, when the lunar anorthosite crust began to form.

The melting points of both creep norites and mare basalt are lower than those of anorthositic rock. Therefore, the existence of these two younger types of lunar material should indicate important events that occurred at a later stage in the evolution of the Moon.
Crip norites are characterized by a high content of elements with a fairly high atomic mass. Due to their large size, these atoms are difficult to “incorporate” into the crystals that form anorthosite. In other words, when anorthositic rock is heated and partially melted, these atoms are essentially "expelled" from the underlying rock. Therefore, it is natural to assume that creep norites were formed during partial melting of anorthosite rock.

Crip Norites are found in the mountainous regions of the Moon. It is not yet clear how the lunar continents were formed. But the same powerful processes that caused the formation of the lunar mountain ranges could also have caused the partial melting of the then young anorthositic crust about 4 billion years ago. Such an assumption would explain the presence of creep norites in mountain ranges similar to those that border the Mare Monsim and Ocean of Storms.

It is obvious that many meteorites have struck the surface of the Moon over the centuries. That is why there are so many craters on it. But the biggest impact marks on the lunar surface are the seas. Perhaps 3.5–4 billion years ago, at least a dozen asteroid-like objects collided violently with the Moon. Under the influence of such destructive impacts, huge craters appeared on the surface of the Moon, “breaking through” to the liquid depths of the young Moon. Lava gushed from the depths of the Moon and over several hundred thousand years filled colossal craters. Dark, smooth seas were formed when flows of molten rock “healed” the wounds inflicted by asteroids. This is the origin of mare basalt, the youngest of the main types of lunar rocks.

On the side of the Moon facing Earth, the crust should be thinner than on the far side. Powerful impacts from planetesimals failed to penetrate the crust on the far side of the Moon. This means that there were no extended spaces flooded with lava, and therefore there are no formations like seas.
Over the past 3 billion years, no significant events have occurred on the Moon. Meteorites just continued to fall onto the surface, although in much smaller quantities than before. The constant bombardment of small bodies gradually loosened the lunar soil, or regolith as it should be properly called. No large body has collided with the Moon since giant kilometer-sized rocks formed the Copernicus and Tycho craters.

Research has shown that the barren, sterile world of the Moon is strikingly different from that of Earth. All traces of the early stages of the evolution of the “actively living” Earth are almost completely erased by the persistent action of wind, rain and snow, while on the airless, lifeless surface of our closest cosmic neighbor, on the contrary, traces of some of the most ancient events that took place in the Solar System are forever imprinted.

V. D. Perov, Yu. I. Stakheev , PhD in Chemistry

SPACE VEHICLES EXPLORE THE MOON (to the 20th anniversary of the launch of Luna-1)

Title: Buy the book "Spacecraft Explore the Moon": feed_id: 5296 pattern_id: 2266 book_

Since the most ancient times of human history, the Moon has always been an object of interest and admiration for people. She inspired poets, amazed scientists, and awakened their creative aspirations. The connection of the Moon with tides and solar eclipses has long been noted, and the mystical and religious interpretations accompanying these phenomena have had a serious impact on human daily life. Since primitive times, the change of lunar phases, the repeated “aging” and “birth” of the Moon have been reflected in the folklore of various peoples and have affected the cultural development of mankind.

And although the nature of the Moon remained unsolved for thousands of years, close interest and intense reflection sometimes led ancient philosophers to astounding guesses. Thus, Anaxagoras assumed that the Moon was made of stone, and Democritus believed that the spots on the Moon were huge mountains and valleys. Aristotle showed that it has the shape of a ball.

Already the ancient Greeks understood that the Moon revolves around the Earth and rotates around its axis with the same period. Aristarchus of Samos, 1900 years before Copernicus, proposed the heliocentric theory of the solar system and calculated that the distance to the Moon is 56 times greater than the radius of the globe. Hipparchus found that the lunar orbit is an oval, inclined 5 degrees to the plane of the Earth's orbit, and estimated the relative distance to the Moon at 59 Earth radii, and its angular size at 31. Truly telescopic precision.

Since 1610, when Galileo saw valleys, mountains, plateaus and large bowl-shaped depressions on the Moon through his telescope, the “geographical” stage of studying this celestial body began. By the end of the 16th century. More than 25 maps of the Moon have already been compiled, of which the most accurate were the maps compiled by Helvelius and J. Cassini. By analogy with the earth's seas, Galileo gave the dark regions of the Moon the name "seas". The view that large craters are volcanic in origin arose intuitively in the 17th century, perhaps by analogy with the Italian volcano Monte Nuovo (located north of Naples), the cinder cone of which appeared in 1538 and grew to a height of 140 m, demonstrating to Renaissance scientists an example of a crater-forming event.

The assumption of the volcanic origin of lunar craters lasted until 1893, when Gilbert's classic work appeared. From this point on, different geological interpretations of lunar landscapes systematically arose. In the 50-60s of our century, scientists came directly to the solution to the sequence of lunar phenomena using the classical geological principle of superposition, which made it possible to construct a scale of relative times and create the first geological map of the Moon. At the same time, an attempt was made to connect the sequence of lunar events with absolute chronology. Some researchers assumed an age of 3–4 billion years for the lunar seas, others (as it turned out later, less successfully) - several tens or hundreds of millions of years.

In 1960, the monographic collection “Moon” appeared, written by a team of Soviet scientists who had been studying the Earth’s natural satellite for many years. It comprehensively and critically presented the data accumulated by that time on the movement, structure, figure of the Moon, information on lunar cartography, the results of optical and radar studies of the atmosphere and surface cover of the Moon, discussed the role of both endogenous (internal, lunar) and exogenous (external) , cosmic) factors in the formation of various features of the lunar relief and physical properties of the outer surface of our satellite. The collection seemed to sum up the “pre-cosmic” period of lunar exploration.

In January 1959, the launch of the Luna-1 automatic station marked the beginning of a qualitatively new stage in the research of our natural satellite. Not only the cislunar outer space, but also the solid body of the Moon became accessible to direct, direct experiment. The launch of Soviet spacecraft to the Moon was also a qualitatively new stage in the development of the entire world cosmonautics. Solving scientific and technical problems related to achieving the second cosmic speed and developing flight methods to other celestial bodies has opened new horizons for science. Experimental methods of geophysics and geology were put into the service of planetology. Cosmonautics provided the opportunity to solve problems that were inaccessible to traditional methods of astronomy, to test a number of theoretical positions and the results of remote intentions, and to obtain new unique experimental material.

The second half of the 1960s in the study of the Moon is characterized by the introduction into operation of automatic stations (AS), capable of delivering scientific instruments to its surface or conducting long-term studies in cislunar space, moving in the orbits of an artificial lunar satellite (ALS). The stage of systematic, painstaking work began to study both the global characteristics of the Moon and the features characteristic of its individual regions.

American specialists have also achieved great success in studying the Moon. The US lunar space program was built largely as a counterweight to the successes of the Soviet Union's astronautics. In the opinion of many American scientists, issues of prestige were given too much attention. The arsenal of American scientists had a variety of apparatus for conducting experiments. These also include automatic devices that, following the Soviet stations, landed on the lunar surface and launched into the orbits of artificial lunar satellites. However, the program of experiments carried out with their help was mainly focused on obtaining the data necessary for the creation of manned Apollo complexes and ensuring the landing of astronauts on the Moon.

The question of the advisability of direct human participation in flights to the Moon and planets at this stage of the development of astronautics has always caused controversy. Space is an environment where human existence is associated with the use of bulky and complex equipment. Its cost is very high, and ensuring reliable operation is not an easy task. Indeed, when flying far from Earth, almost any failure in the systems puts the crew on the brink of death. The days have not yet faded from memory when the whole world watched with bated breath as American astronauts fought for their lives, placed in the most difficult conditions by an accident that led to malfunctions in the systems of the Apollo 13 spacecraft on its way to the Moon.

From its first steps, the Soviet lunar space program was focused on a consistent and systematic solution to pressing problems of selenology. Its rational construction, the desire to correctly correlate scientific goals and means for their implementation brought great success and led the Soviet cosmonautics to many outstanding priority achievements, while maintaining an acceptable level of material costs, without excessively straining the country's economic resources and without harming the development of other areas of science and technology , sectors of the national economy.

This was largely determined by the fact that the Soviet space program was based on the use of automatic research tools. The high level of development of the theory of automatic control, great successes in the practice of designing automatic machines for various purposes, the rapid progress of radio electronics, radio engineering and other branches of science and technology have made it possible to create spacecraft with wide functional capabilities, capable of performing complex operations and operating reliably in extreme conditions for long periods of time. time.

The flights of Soviet automatic space reconnaissance aircraft made it possible, for the first time in world cosmonautics, to solve such fundamental problems as completing the Earth-Moon flight, obtaining photographs of the far side of the Moon, launching an artificial lunar satellite into orbit, performing a soft landing on the surface and transmitting the lunar landscape to telepanoramas, delivery to Earth samples of lunar soil using an automatic device, the creation of mobile laboratories "Lunokhod" with a variety of scientific equipment for long-term complex experiments in the process of moving over long distances.

The brochure presented to the attention of readers tells about the main types of Soviet automatic lunar stations and their equipment, provides brief information about the scientific results obtained with the help of space technology, and provides some information about future directions in the exploration and development of the Moon.

THE FIRST AUTOMATIC MOON SCOUTS

The Soviet automatic stations of the first generation, delivered to the lunar region using Soviet space launch vehicles, include the Luna-1, -2, -3 AS (see Appendix). At this stage, Soviet cosmonautics solved such problems as the flight of a spacecraft near the Moon (“Luna-1”), its targeted entry into a given area of ​​the lunar hemisphere facing the Earth (“Luna-2”), its flyby and photographing the far side of the Moon. (“Luna-3”).

The stations were launched onto the Earth-Moon route, starting from the surface of the Earth, and not from the orbit of its artificial satellite, as has become customary now. After the completion of the propulsion system, the station undocked from the last stage of the launch vehicle and then made an uncontrolled flight. At the same time, to ensure movement along the desired trajectory, it was necessary to extremely accurately maintain the specified movement parameters at the end of the active phase of the launch vehicle, reliable and accurate functioning of all systems, especially the automation of the propulsion system and the control system.

The flights of the first automatic stations to the Moon were a new outstanding achievement of the young Soviet cosmonautics, a convincing demonstration of the capabilities of science and technology of the Soviet Union. Just over two years have passed since the launch of the first artificial Earth satellite into low-Earth orbit, and Soviet scientists and designers have already solved a fundamentally new problem - placing an automatic vehicle on a flight path in a heliocentric orbit.

Rice. 1. Automatic station “Luna-1”

In order for the station to become the first artificial planet, it needed to reach a speed exceeding the second cosmic speed and overcome Earth's gravity. This task was achieved through the creation of a powerful launch vehicle, characterized by high design excellence, equipped with a highly efficient propulsion system and an advanced control system. The complexity of the problem of creating a missile system of this class is illustrated by the difficulties that American specialists encountered at a similar stage of space research. For example, out of nine launches of the first automatic vehicles of the Pioneer series, intended for the exploration of the Moon and cislunar space, only one was completely successful.

Let's consider what the first Soviet reconnaissance aircraft of interplanetary routes were and how their flights to the Moon were carried out.

The Luna-1 station (Fig. 1) was a spherical sealed container, the shell of which was made of an aluminum-magnesium alloy. Inside the container were placed electronic components of scientific equipment, radio equipment, and chemical current sources. A magnetometer for measuring the parameters of the magnetic fields of the Earth and the Moon, proton traps, sensors for recording meteoric particles, and radio antennas were installed on the container body. In order for the station equipment to operate under acceptable temperature conditions, the container was filled with neutral gas, the forced circulation of which was ensured by a special fan. Excess heat was radiated into space through the container shell.

After the launch, when reaching a speed exceeding the second cosmic speed, and after turning off the engine, the station was separated from the launch vehicle and, as mentioned above, flew autonomously.

On January 4, 1959, the Luna-1 station approached the Moon at a distance of 5000–6000 km, and then, entering a heliocentric orbit, became the first artificial planet in the Solar System.

AS "Luna-2" had a similar design to "Luna-1" and equipment similar to it. On September 14, 1959, it reached the surface of the Moon west of the Mare Serenity at a point with selenocentric latitude +30° and longitude 0°. For the first time in the history of astronautics, a flight was made from Earth to another celestial body. To commemorate this memorable event, pennants with the image of the Coat of Arms of the Soviet Union and the inscription “Union of Soviet Socialist Republics” were delivered to the Moon. September. 1959."

Carrying out a station flight to a precisely specified area of ​​the Moon is a task of extreme complexity. Today, twenty years later, when automata have already visited Venus and Mars, made voyages to Mercury and Jupiter, when man has more than once left traces on the “dusty paths” of our natural satellite, hitting the Moon when “shot” from the Earth seems a simple matter. But at that time, the first flight of an automatic station to the Moon was rightfully perceived by the world community as an outstanding scientific and technical achievement.

The creators of space technology and the specialists preparing the flight of the Luna-2 station faced many difficult questions. After all, the solution to the problem of “simple hitting” the Moon required that the automatic control system maintain the final speed of the launch vehicle with an accuracy of several meters per second, and the deviation of the actual speed from the calculated one by only 0.01% (1 m/s) “led away” the station would be 250 km away from the expected meeting point with the Moon. In order not to miss the Moon, you need to maintain the angular position of the launch vehicle's velocity vector with an accuracy of 0.1°. At the same time, an error of just 1 “displaced” the lunar landing point by 200 km.

There were other difficulties, and one of them was organizing and preparing the launch vehicle for launch. The Earth and the Moon are in complex mutual motion, so for a flight to a given area of ​​the Moon it is very important to accurately maintain the moment of launch. So, a miss of the same 200 km is obtained when the start time deviates by only 10 s! The second Soviet space rocket with the Luna-2 station on board started its flight with a deviation from the set time of only 1 s.

The first space “photographer” was the automatic station “Luna-3”. Its main task is to photograph the far side of the Moon, which is inaccessible for exploration from Earth. In this regard, the station's trajectory had to satisfy a number of specific requirements. Firstly, care had to be taken to ensure optimal shooting conditions. It was decided that the distance of the AS to the Moon when photographing would be 60–70 thousand km, and the Moon, the station and the Sun should be approximately on the same straight line.

Secondly, it was necessary to ensure good radio communication conditions with the station when transmitting images to Earth. In addition, in order to conduct scientific experiments accompanying the main task of the flight, it was necessary for the station to exist in space longer, that is, so that during its flight near the Earth it did not enter the dense layers of the atmosphere.

For the movement of the Luna-3 station, they chose a trajectory around the Moon taking into account the so-called “perturbation” maneuver, in which a change in the initial trajectory of the device occurs not due to the operation of the onboard engine (the station did not have one), but due to the influence of the gravitational field of the Moon itself. Moons.

Thus, even at the dawn of astronautics, Soviet specialists implemented a very interesting and promising method for maneuvering automatic vehicles during interplanetary flights. The use of a “perturbation” maneuver allows you to change the flight trajectory without using onboard propulsion systems, which ultimately makes it possible to increase the weight allocated to scientific equipment due to saved fuel. This method was later repeatedly used in the practice of interplanetary flights.

On October 6, 1959, Luna-3 passed near the Moon at a distance of 7900 km from its center, went around it and entered an elliptical satellite orbit with an apogee of 480,000 km from the center of the Earth and a perigee of 47,500 km. The influence of the lunar gravitational field reduced the apogee of the trajectory by approximately one and a half times compared to the initial orbit and increased the perigee. In addition, the direction of movement of the station has changed. It approached the Earth not from the southern hemisphere, but from the northern, within direct visibility of communication points on the territory of the USSR.

Structurally, the Luna-3 station (Fig. 2) consisted of a sealed cylindrical body with spherical bottoms. Solar panels, radio complex antennas, and sensitive elements of scientific equipment were installed on the outer surface. The upper bottom had a camera porthole with a lid that automatically opened when taking photographs. In the upper and lower bottoms there were small windows for the solar sensors of the attitude control system. Micromotors of the attitude control system were mounted on the lower bottom.

Rice. 2. Automatic station “Luna-3”

On-board service equipment, including station blocks and devices, scientific instruments and chemical current sources, was placed inside the housing, where the necessary thermal conditions were maintained. The removal of heat generated by operating devices was provided by a radiator with shutters to regulate heat transfer.

The station's camera had lenses with focal lengths of 200 and 500 mm for photographing the Moon at various scales. Photographing was carried out on a special 35 mm film that can withstand high temperatures. The captured film was automatically developed, fixed, dried and prepared for transmitting images to Earth.

The broadcast was carried out using a television system. The conversion of the negative image on the film into electrical signals was carried out by a translucent cathode ray tube with high resolution and a highly stable photomultiplier. The transmission could be carried out in a slow mode (when communicating at large distances) and fast (when approaching the Earth). Depending on the transmission conditions, the number of lines into which the image was decomposed could vary. The maximum number of lines is 1000 per frame.

To take photographs, after the AS, moving along the trajectory, reached the required position relative to the Moon and the Sun, the autonomous orientation system was put into operation. With the help of this system, the random rotation of the station that arose after separation from the last stage of the launch vehicle was eliminated, and then, with the help of solar sensors, the AS was oriented in the Sun-Moon direction (the optical axes of the camera lenses were directed towards the Moon). After achieving an accurate orientation, when the Moon fell into the field of view of a special optical device, a command to photograph was automatically given. During the entire photographic session, the orientation system maintained constant pointing of the equipment towards the Moon.

What is the scientific significance of the results of the flights of the first messengers to the Moon?

Already at the first stage of lunar research using automatic space devices, the most important planetological scientific data was obtained. It was discovered that the Moon does not have a noticeable magnetic field of its own or a radiation belt. The lunar magnetic field was not registered by the equipment of the Luna-2 station, which had a lower sensitivity threshold of 60 gammas, and, thus, the strength of the lunar magnetic field turned out to be 100–400 times less than the magnetic field strength at the Earth's surface.

Another interesting conclusion was that the Moon still has an atmosphere, albeit an extremely rarefied one. This was evidenced by an increase in the density of the gas component as it approached the Moon.

Using an “artificial comet” - a cloud of sodium vapor ejected into space and glowing under the influence of solar radiation - the gaseous environment of interplanetary space was studied. Observation of this cloud also made it possible to clarify the parameters of the station’s movement along the trajectory.

Photographing the far side of the Moon, carried out by the Luna-3 station, for the first time made it possible to see about 2/3 of the surface and discover about 400 objects, the most noticeable of which were given the names of prominent scientists. The asymmetry of the visible and invisible sides of the Moon was unexpected. On the reverse side, as it turned out, a continental shield with an increased density of craters predominates and there are practically no marine areas, so characteristic of the well-known, visible side.

Based on the photographs obtained, the first atlas and map of the far side of the Moon were compiled and a lunar globe was made. Thus, a major step was taken towards the “great geographical discoveries” on the Moon.

The first flights to the Moon were of great importance for the development of astronautics, and, in particular, for the creation of interplanetary automatic stations, the accumulation of experience and the development of technical means and methods for long-term interplanetary flights. They certainly contributed to the future successes of the Soviet Union in the study of our closest neighbors in the solar system - the planets Venus and Mars.

SOFT LANDING AND ARTIFICIAL MOON SATELLITES

The first sounding, reconnaissance, flights to the Moon not only brought many interesting and valuable scientific results, but also helped formulate new directions for research into our closest cosmic neighbor. On the agenda was the question of studying the global properties of this cosmic body, as well as conducting research to identify regional features of the structure of the lunar surface.

To solve these problems, it was necessary to create spacecraft capable of delivering scientific equipment to various areas of the Moon or conducting long-term studies in cislunar space from the orbits of its artificial satellites. A whole complex of scientific and technical problems has arisen related to ensuring greater accuracy of launching spacecraft onto the required flight trajectories, monitoring and controlling their movement, developing methods and creating means of orienting spacecraft to celestial bodies and compact, reliable and efficient rocket launchers. engines that allow multiple activations and allow thrust adjustment over a wide range (to correct motion trajectories and braking when performing a soft landing or transition to an ISL orbit).

The stations of this generation included AS Luna-9, -13, which performed soft landings on Luka, as well as Luna-10, -11, -12, -14, launched into lunar orbits (see Appendix). They included a liquid jet engine and fuel tanks, a container with scientific equipment and systems to ensure its operation, as well as radio equipment for transmitting commands from the Earth to the AS and information from the AS to Earth, automatic devices ensuring the operation of all units in a certain sequences.

Depending on the flight mission (soft landing on the Moon or placing the station into lunar orbit), the set of service systems and their mode of operation, the composition of the scientific equipment and its layout varied.

The Soviet station Luna-9 became the first spacecraft in human history to make a soft landing on the Moon. The set of devices that ensured the delivery of the container with equipment to the lunar surface included a correction and braking propulsion system, radio devices and control system units, and power supplies.

The propulsion system of the AS consisted of a single-chamber liquid-propellant rocket engine and control nozzles, a spherical oxidizer tank, which was the main power element of the station, and a torus-shaped fuel tank. The engine used fuel consisting of a nitric acid oxidizer and amine-based fuel. The components were supplied to the combustion chamber by a turbopump unit. The liquid-propellant rocket engine developed a thrust of 4640 kg at a pressure in the combustion chamber of about 64 kg/sq. see. The propulsion system provided two-time activation necessary for trajectory correction during flight and braking before landing. During correction, the engine operated with constant thrust, and during landing its value was adjusted over a wide range.

Automatic devices that ensure operations during the entire flight were installed in a sealed compartment, and units needed only during the flight to the Moon (before landing operations) were placed in special compartments that were reset before braking began. This layout made it possible to significantly reduce the mass of service systems before landing and significantly increase the mass of the payload.

The final stage of the flight (Fig. 3) began 6 hours before landing - after data was transferred to the AS to set up the control system. 2 hours before the meeting with the Moon, the systems were prepared for braking using radio commands from the Earth. The order of further operations was developed by the logical on-board devices of the control system, which also ensured the orientation of the station based on the operation of optical sensors tracking the Earth and the Sun (while the engine axis was directed towards the center of the Moon).

After the radio altimeter registered that the altitude of the AS above the surface was about 75 km, the liquid-propellant rocket engine began braking. When the liquid-propellant rocket engine was launched, the jettisoned compartments were separated, and the AS was stabilized with the help of control nozzles using the exhaust gas of the turbopump unit. The amount of engine thrust was regulated according to a certain law, so that the required landing speed and the station reached a given height above the lunar surface at the end of braking.

Due to the fact that at the time of the flight of the Luna-9 AS there were no accurate data on the properties of the lunar surface, the landing system was designed for a wide range of soil characteristics - from rocky to very loose. The station's landing container was placed in an elastic shell, which was inflated with compressed gas before landing. Immediately before contact with the Moon, the spherical shell with the container enclosed in it was separated from the instrument compartment, fell to the surface and, after bouncing several times, stopped. At the same time, it broke into two parts, was thrown away, and the AS descent module ended up on the ground.

Rice. 3. Flight diagram of the automatic station “Luna-9”

The descent vehicle of the AS Luna-9 is close in shape to a sphere. Four lobe antennas are attached to it externally, as well as four whip antennas with brightness standards suspended on them (to assess the surface albedo at the landing site) and three dihedral mirrors. At the top of the container there was a television camera.

During flight, the antennas and mirrors were folded. The upper part of the descent module is covered with lobe antennas (it was ovoid in shape). Its center of gravity was located in the lower part, which ensured the correct position on the ground - under almost any landing conditions.

4 minutes after landing, on command from the software device, the antennas opened, and the equipment was brought into working condition. The open lobes served to transmit information, and the whip antennas were used to receive signals from the Earth. During the flight, radio signals were received and transmitted through lobe antennas.

The mass of the descent vehicle is about 100 kg, the diameter and height (with antennas open) are 160 and 112 cm.

To obtain images of the lunar landscape, an optical-mechanical system was installed on the Luna-9 AS, which included a lens, a diaphragm that forms the image element, and a movable mirror. Swinging in the vertical plane, which was created using a special profiled cam, the mirror carried out horizontal scanning, and its movement in the horizontal plane provided frame panoramic scanning. Both of these movements were produced by one electric motor with a stabilized rotation speed. Moreover, the camera’s unfolding device had several operating modes: transmission could be carried out at a speed of one line per 1 s with a full panorama transmission time of 100 minutes, but an accelerated view of the surrounding area could also be used. In this case, the panorama transmission time was reduced to 20 minutes.

The vertical angle of view of the camera was chosen to be 29° - 18° down and 11° up from the plane perpendicular to the camera's rotation axis. This was done in order to obtain predominantly an image of the surface. Since the vertical axis of the descent vehicle, when landing on a horizontal platform, had an inclination of 16°, areas of the surface starting from a distance of 1.5 m fell into the field of view of the television camera, and therefore the lens was focused to obtain a sharp image from 1.5 m to “infinity” "

The temperature regime of the descent vehicle was ensured by effective protection of the container from the influence of the external environment and the removal of excess heat into the surrounding space. The first problem was solved using the thermal insulation available on the body, the second - using an active thermal control system. The internal volume of the sealed instrument compartment was filled with gas, and when it was mixed, heat from the equipment was transferred to special tanks with water. When the temperature increased above the required norm, the electrovalve opened, water evaporated into a vacuum and heat was removed from the radiators. To eliminate overheating of the television camera, a heat-insulating screen was installed on its upper part, and the outer surface was covered with gold.

Luna-13 (Fig. 4), the second Soviet station to land on the Moon, had a similar design. Its task included the first direct instrumental study of the physical characteristics of the lunar surface, for which a ground meter-penetrometer, radiation density meter, radiometers, and a system of accelerometers were used.

The soil meter-penetrometer consisted of a plastic body, the lower part of which was a ring stamp with an outer diameter of 12 cm and an inner diameter of 7.15 cm, as well as a titanium indenter with a lower part made in the form of a cone (the angle at the apex of the cone was 103°, the diameter of the base 3.5 cm). The soil meter was attached to the end of a remote mechanism, which is a folding multi-link that opens under the action of a spring and ensures that the device is carried out to a distance of 1.5 m from the station.

Rice. 4. Automatic station "Luna-13"

After the device was installed in the operating position, a command was given to start a solid propellant rocket engine with a given thrust and operating time, placed in the indenter housing. The depth of immersion of the indenter into the soil was recorded using a potentiometer with a sliding contact. The assessment of the mechanical properties of lunar soil was carried out based on the results of laboratory studies of analogous terrestrial soils, as well as experiments in a vacuum chamber and on board an aircraft flying along a trajectory that allows simulating the acceleration of gravity on the Moon.

The radiation density meter was intended to determine the density of the surface layer of soil to a depth of 15 cm. The density meter sensor was mounted on an external mechanism and placed on the ground, and the readings received were sent to an electronic unit located in the sealed housing of the station and transmitted to the Earth via telemetry channels. The density meter sensor included a source of gamma radiation (a radioactive isotope), as well as counters for measuring the registration of “lunar” gamma quanta: gamma radiation from the source, falling on the ground, was partially absorbed by it, but was partially scattered and fell on the counters. In order to eliminate direct contact of the source radiation with the counters, a special lead screen was placed between them and the isotope source. The interpretation of the sensor readings was carried out on the basis of ground calibration of the device, using various materials in the density range p(ro) = 0.16-2.6 g/cubic. cm.

The heat flow from the lunar surface was measured by four sensors, positioned so that at least one of them was never obscured by the station itself and its inlet was not directed toward the Sun or into the sky. The radiometer sensors were mounted on hinged brackets, folded during flight and opened when the station's lobe antennas were opened (after landing on the lunar surface).

The dynamograph was a system of three accelerometers oriented in three mutually perpendicular directions. The accelerometers were located on the instrument frame inside the lander; their signals, corresponding to the duration and magnitude of the dynamic overload, were received by an integrating and storage device and transmitted to Earth using a radio telemetry system.

The flight of the Soviet AS Luna-9 began a new stage in selenology - the stage of conducting experiments directly on the surface of the Moon. A set of data on the lunar surface obtained by the Luna-9 station put an end to disputes about the structure and strength of the upper layers of the soil. It has been proven that the surface of the Moon is strong enough to not only withstand the static weight of the device without significant deformation, but also to “resist” after its impact when landing on the lunar surface. Analysis of the panoramas revealed the nature of the structure of the lunar soil and the distribution of small craters and stones on it. It is very important that for the first time it became possible to examine surface details with dimensions of 1–2 mm, and a random shift of the station made it possible to obtain a stereo pair for the first panorama; When analyzing the stereo image, it was possible to more accurately understand the surface topography. It turned out that it is smoother than previously thought based on ground-based observations.

The Luna-13 station brought the first objective quantitative data on the physical and mechanical characteristics of the lunar soil, obtained by direct measurements. The new information not only had great scientific significance, but was also used in the future to calculate the design elements of much larger stations of the next generation, capable of carrying drilling equipment, Luna-Earth rockets that delivered lunar soil to Earth and automatic laboratories "Lunokhod" .

Fig 5. Automatic station “Luna-10”

The artificial satellites of the Moon of this period had a significant mass according to the concepts of that time and were equipped with numerous scientific instruments. For example, the mass of the Luna-10 ISL was 245 kg, while the mass of the Luna-9 station’s descent module was about 100 kg. The increase in the mass of an ASUS with an ISL compared to others is explained by the fact that to perform the maneuver of transferring a spacecraft into a lunar orbit, significantly less fuel is required than when performing a soft landing on the Moon, and therefore, due to fuel “savings,” more instruments can be placed on such an ASUS .

The artificial satellites of the Moon had on board scientific instruments, radio equipment, power supplies, etc. The required thermal conditions were maintained using a special thermal control system. The ISL scientific equipment could include a wide variety of instruments. At the Luna-10 station (Fig. 5), for example, the following were installed: a magnetometer to clarify the lower limit of the Moon’s magnetic field, a gamma spectrometer to study the spectral composition and intensity of gamma radiation from the rocks that make up the surface of the Moon, instruments for recording corpuscular solar and cosmic radiation, charged particles of the earth's magnetosphere. ion traps for studying the solar wind and the lunar ionosphere, sensors for recording micrometeorites on the Earth-Moon flight route and in the vicinity of the Moon, an infrared sensor for recording thermal radiation from the Moon.

The scientific onboard equipment of the Luna-11 station included instruments for recording gamma and X-ray radiation from the surface (which made it possible to obtain data on the chemical composition of lunar rocks), sensors for studying the characteristics of meteor showers and hard corpuscular radiation in the lunar space, and instruments for measuring long-wave cosmic radio emission.

One of the main tasks of the third Soviet ISL, the Luna-12 automatic station, was to carry out large-scale photography of the lunar surface, carried out from various altitudes of the ISL orbit. The area covered by each image was 25 square meters. km, and on them it was possible to distinguish surface details measuring 5-20 m. A phototelevision device automatically processed the film and then transmitted the images to Earth. In addition to photographic experiments, the station continued research begun on the flights of previous stations.

Automatic spacecraft located in lunar orbits are an effective tool for identifying global features of the structure of the Moon, the characteristics and properties of its surface, and studying the cislunar environment. For example, fundamental research carried out from the orbits of artificial lunar satellites includes determining the global characteristics of the chemical composition of lunar rocks. Finding out the composition of the rocks that make up the surface of the Moon provided the key to testing geochemical concepts about the evolution of celestial bodies.

A number of methods have been proposed for remote analysis of the chemical composition of lunar soil. Among them are the registration of neutrons produced during the interaction of cosmic rays with surface matter, the measurement of X-ray radiation excited by solar radiation, and some others. A scintillation gamma spectrometer was installed on the Luna-10 AS, which measured the spectrum of lunar gamma radiation. During its operation on board this ISL, nine gamma radiation spectra were obtained in two energy intervals of 0.15-0.16 and 0.3-3.2 MeV, and the radiation intensity was measured at 39 points of the lunar surface in the energy interval 0 .3–0.7 eV.

A comparison of the obtained spectra with the calibration spectra, as well as with the spectra of terrestrial materials, showed that the surface of the Moon on a global scale is composed of rocks of a basaltic nature. As a result, the assumptions that the surface of the Moon has a granitic or ultramafic composition, or that it is lined with a layer of chondritic meteorites or tektites, were rejected. This provided an important argument in favor of the igneous origin of lunar rocks.

Photographic photography of the lunar surface was used for astronomical selenodesis and selenographic study of the Moon during cartographic work. The resulting images (with different resolutions) of surface details made it possible to study the characteristics of the lunar relief, the distribution and structural features of tectonic structures, and the sequence of lava outpourings in marine areas.

Several magnetographic sections of the lunar space, made using ISL magnetometers, revealed the presence of a weak magnetic field caused by the interaction of the Moon with the solar wind. Plasma experiments marked the beginning of the study of the distribution of charged particles and the conditions for their existence in cislunar space as part of the general laws inherent in the process of interaction of solar wind plasma with the planets of the Solar System.

Analysis of changes in the parameters of the motion of the ISL, carried out by ground-based radio engineering complexes during the flight of spacecraft in various orbits, made it possible to carry out a preliminary determination of the gravitational field of the Moon. It turned out that the disturbances in the station's motion due to the non-centrality of the Moon's gravitational field are 5–6 times greater than the disturbances caused by the attraction of the Earth and the Sun. The asymmetry of the field on the visible and far sides of the Moon was established.

Systematic long-term observations of changes in orbital parameters have made it possible to significantly clarify the ratio of the masses of the Moon and the Earth, the shape of the Moon and its movement.

ISL flights brought a significant amount of information about the conditions and stability of radio signals transmitted from the Earth to the AS and back. Very interesting information was obtained about the characteristics of the reflection of radio waves by the surface of the Moon, which made it possible not only to identify changes in the characteristics of the reflection of radio waves, but also to estimate the dielectric constant and density of matter in various regions of the Moon.

BEHIND THE MOONSTONE. LUNOROVERS

By the 70s, a new generation of “lunar” spacecraft was being created in the Soviet Union, which made it possible to solve a wide range of scientific problems. The basis for the constructive construction of these automatic stations was their division into stages, the first of which (landing) was a unified autonomous rocket unit, providing trajectory correction during the Earth-Moon flight, entering selenocentric orbits with a wide range of orbital parameters, maneuvering in cislunar space and, finally, landing in various areas of the lunar surface. The stage could carry various equipment as a payload.

The creation of new generation stations has become a decisive factor in the implementation of outstanding experiments in the field of studying the Moon using spacecraft - the collection of lunar soil and its delivery to Earth and the work of mobile laboratories on the lunar surface. However, before moving directly to these experiments, we will consider in more detail the design elements of the new speakers and their equipment.

The landing stage included a fuel tank system, variable-thrust liquid propellant rocket engines, instrument compartments, and shock-absorbing supports. Micromotors and attitude control system sensors, as well as containers with the engine working fluid and radio complex antennas were mounted on the landing stage.

The main power element of the landing stage was the fuel tank unit, which consisted of four spherical containers connected into a single structure. The propulsion system and all the necessary equipment were attached to them. Shock-absorbing supports were attached to the tanks from below.

The landing stage had two jettisonable compartments, each of which consisted of two fuel tanks and a sealed container located between them with equipment for the celestial orientation system and radio complex automation. Special compartments (they were discarded before the final stage of braking during landing) housed the equipment and fuel necessary for the flight to the Moon.

The propulsion system of the new speakers consisted of a main single-chamber engine, a two-chamber low-thrust engine, control gas nozzles and a fuel supply system to the combustion chamber.

The main AC engine was intended for trajectory correction and braking. The thrusters were running just before landing. The main engine had a pump supply of fuel to the combustion chamber and allowed for repeated activation. It worked in three modes - in the thrust range of 750-1930 kg. The two-chamber low-thrust engine had a displacement fuel supply, could be turned on only once and operated in three modes - in the thrust range from 210 to 350 kg.

Each of the landing gear supports, designed to dampen the kinetic energy of the station at the moment of touching the lunar surface and to maintain a stable position after landing, consisted of a V-shaped strut, a support disk and a shock absorber.

During the launch of the launch vehicle with the AS, the supports were raised and in a folded state. After the station was separated from the last stage of the launch vehicle, the supports were opened into the working position under the action of a spring.

The AS flight to the Moon was now carried out in several stages. After separation from the last stage and the station entering the flight route, the coordination and computing center, based on trajectory measurements, determining the difference between the actual trajectory parameters and the calculated ones, made a decision on the necessary correction, calculating the time the engine was turned on and the direction of the corrective pulse. All this data in the form of commands was transmitted on board the AS and stored in the memory unit of the control system.

Rice. 6. Scheme of descent of the Luna-16 AS to the lunar surface

Before turning on the correction engine, the station had to be turned around and its orientation in space changed accordingly. At the same time, the speakers were first brought to the so-called “base position”, when the sensitive elements of the orientation system “see” the Sun and the Earth. Then, using turns around two axes, the speaker was installed in its original position. After the engine was turned on at the calculated time by a signal from the software-timing device, the gyroscopic devices, which “remembered” the desired position of the station, with the help of control elements “parried” all disturbances that arose during the operation of the propulsion system.

As soon as the speed of the station changed by the required amount, the automation gave a command to turn off the engine. According to a similar scheme, the station was launched into a lunar orbit or the orbital motion was corrected.

After maneuvering in the lunar space (the so-called landing orbit formation process), the motion parameters were clarified, and codograms were issued on board the AS, defining the sequence of operations during landing. When the AS was brought to the starting position for braking, the hinged compartments were discarded, the propulsion system was turned on, and the descent to the lunar surface began (Fig. 6). Then, when the station received the necessary braking impulse, the engine was turned off and the station made a stabilized ballistic descent, while the vertical and horizontal components of the velocity were continuously measured using a Doppler measuring system and an altimeter.

At certain values ​​of the vertical component of the movement speed and height above the surface, the main engine was turned on again, and after its operation was completed, the two-chamber low-thrust engine was started, which finally extinguished the speed of the AS (it was turned off by a command given from the on-board gamma altimeter).

To illustrate the operation of the main engine, we present the values ​​of heights above the surface at characteristic points of the descent section of the Luna-17 AS. The first activation of the braking engine occurred at an altitude of 22 km above the lunar surface at a longitudinal speed of the AC of 1692 m/s. At an altitude of 2.3 km the engine turned off. Its second switching on occurred at an altitude of about 700 m, and switching off at an altitude of 20 m. At the moment of touching the surface, the station had a vertical descent speed of about 3.5 m/s, the lateral component was approximately 0.5 m/s.

Automatic stations made on the basis of a unified landing stage include AS “Luna-16, -20, -24”, which delivered soil from various regions of the Moon to Earth, as well as “Luna-17, -21”, on which mobile self-propelled scientific laboratories “Lunokhod-1, -2” (see Appendix).

Rice. 7. Diagram of the soil intake device and the return vehicle of the Luna-16 stations

Operations to collect lunar soil were carried out using soil sampling mechanisms. The soil intake device, used, for example, during the flights of the Luna-16, -20 AS (Fig. 7), consisted of a rod with a drilling rig mounted on it and electromechanical drives that moved the rod in the vertical and horizontal planes. The working part of the drilling machine was a vibro-impact drill with cutters at the end (it was hollow inside).

Drilling mechanisms ensured work with rocks having a wide range of physical and mechanical properties - from silty-sandy to rocky. The maximum drilling depth was 35 cm. This equipment was driven by electric motors; the speed of the drill's penetration into the ground and the power consumed by the electric motors were controlled from the Earth telemetrically.

Drilling during operation of the Luna-16 AS lasted about 6 minutes and was carried out to full depth. At the end of the working stroke, the electric motors of the drilling rig were automatically turned off. The mass of the extracted sample was about 100 g.

The process of drilling soil in the mainland area of ​​the Luna-20 AS was more complex. The drill automatically stopped several times due to the fact that the current in the electric motors exceeded the permissible value. The well was drilled to a depth of about 300 cm (there is a typo in the text, “m” is given). The mass of the extracted sample was 50 g.

After completing all the necessary operations, the machine was moved away from the ground, raised and turned 180 degrees, and then the drill with the soil inside it was placed into the hermetically sealed capsule of the return vehicle.

The Luna-24 automatic station was equipped with a device for deep drilling. This device included a drilling head moving along special guides attached to the landing stage and the Luna-Earth rocket, a drill rod with a crown, a drilling head feeding mechanism, an elastic soil carrier for placing the extracted soil, mechanisms for winding the soil carrier with soil on a special drum and for placing it in the recovery apparatus.

Drilling was carried out by rotary or impact-rotational movements of the tool. The operating mode was selected automatically or by commands from the Earth, depending on the excavation conditions, strength and viscosity of the soil. The installation made it possible to obtain a soil core with a diameter of 8 mm, the maximum working stroke of the drill head was 2.6 m. The mass of the sample delivered to Earth was 170 g (the actual length of the extracted core was 1600 mm).

The delivery of lunar soil to Earth was carried out using the take-off stage of the AS, after the launch from the Moon of the so-called “Lunar rocket”, which consisted of a propulsion system (having ball cylinders with fuel and a rocket engine with pumping of fuel components into the combustion chamber), an instrument compartment with control equipment and the return vehicle, in which the lunar soil made the Moon-Earth flight, descent in the atmosphere and landing.

The return vehicle had a spherical shape and was installed at the top of the instrument compartment. Its shell was made of metal with a special heat-protective coating, protecting it from exposure to high temperatures during the ballistic descent in dense layers of the atmosphere. The return vehicle contained a cylindrical hermetically sealed container for lunar soil, a parachute system, automatic elements that control the activation of the parachute system, batteries, direction-finding transmitters, radio antennas and elastic gas-filled cylinders to ensure the required position of the vehicle on the Earth's surface.

The launch of the “Moon Rocket” to Earth took place in the direction of the lunar local vertical. This direction was “remembered” by the control system during landing on the Moon. If the longitudinal axis of the take-off stage could be deviated from the vertical during take-off, the control system issued the necessary commands, thanks to which the rocket entered the desired trajectory.

When the required acceleration speed was reached (for example, for the Luna-16 AS it was 2708 m/s), the engine was turned off, and the Lunar Rocket then followed a ballistic trajectory. During the flight, the on-board radio complex provided communication with the Earth and trajectory measurements to clarify the landing site of the return vehicle. When approaching the Earth, a command was transmitted on board the spacecraft to detonate the squibs of the metal tapes securing the return vehicle to the instrument compartment, and after, thanks to the movement in the atmosphere, the spacecraft reduced its speed to a certain value, the parachute system was put into operation.

Self-propelled vehicles controlled from the Earth, Lunokhod-1, -2, designed to conduct complex scientific research during long-term operation on the lunar surface, were delivered using the Luna-17, -21 AS.

“Lunokhovers” were placed on the landing stage and were attached with their bottoms to four vertical posts through special pyro units. On the landing stage, ladders were also installed for the mobile laboratory to descend to the lunar surface. During the flight of the AS, the ladders were folded, and after landing they opened under the action of special springs.

The Lunokhod vehicles (total mass about 800 kg) (Fig. 8) consisted of two main parts: the instrument compartment and the self-propelled chassis. The instrument compartment was intended to accommodate scientific equipment and devices that needed to be protected from exposure to outer space conditions. The upper part of the instrument compartment housing was used as a radiator in the thermal control system and was closed with a lid. During the lunar night, the lid was closed and protected the compartment from excessive heat loss, while during the lunar day it was open, facilitating the release of excess heat into the space. Solar battery elements were placed on the inner surface of the cover. The cover could be installed at different angles and provide optimal illumination of the solar panel during operation of the self-propelled vehicle.

The required thermal conditions of the equipment were maintained by both passive and active methods. Screen-vacuum insulation on the outer surface of the instrument compartment was used as thermal protection (passive method). Active thermal protection was carried out by regulating the temperature of the gas circulating inside the compartment. Using a fan and a special damper, the gas was directed to the hot or cold circuits of the thermal control system. Local blowing of some devices using separate gas supply channels was also used.

Rice. 8. Diagram of the self-propelled vehicle “Lunokhod-1”

The hot circuit included a heating unit located at the rear of the Lunokhod (outside the instrument compartment). The heat in the block was generated during the decay of a radioactive isotope.

The instrument compartment was installed on an eight-wheeled chassis, which had high maneuverability with relatively low weight and energy consumption. The wheels of the Lunokhod (Fig. 9) had an independent suspension: an electromechanical drive was built into the hub of each wheel (therefore, each of them was a drive). The elastic elements here were torsion bars; the fastening of the wheels ensured overcoming ledges 400 mm high without hitting the supports.

The wheel drive consisted of a direct current electric motor, the brushes of which were made of a special material designed to work in a vacuum, as well as a gearbox and a mechanical brake with electromagnetic control. The transmission output shaft had a local weakening of the section so that it could be destroyed by detonating the pyroelectric device upon command from the Earth (in case it jammed). In this case, this wheel became a driven wheel and did not interfere with movement: the design of the chassis allowed the simultaneous unlocking of five of the eight wheels without loss of mobility of the Lunokhod.

Rice. 9. Diagram of the Lunokhod-1 wheel design

The self-propelled vehicle was controlled by commands from the Earth by a crew consisting of a commander, driver, navigator, flight engineer and highly directional antenna operator. The information required for control included a television image of the area in front of the Lunokhod, telemetric data from on-board gyroscopes and distance sensors, information about the state of on-board systems, the roll and trim of the self-propelled vehicle, wheel motor current, etc.

The crew commander provided general management of the work and made the final decision based on information received from the navigator, flight engineer and driver. The driver directly controlled the Lunokhod, and the navigator performed navigation calculations, issued recommendations on the direction of movement, and was responsible for monitoring the path traveled. The flight engineer monitored the state of all systems of the device, and the operator of the highly directional antenna monitored its correct orientation and ensured optimal communication conditions.

A special television device was used to solve problems related to the control of the Lunokhod. The electronic low-frame television system included in it transmitted operational information used when “driving” the device. In the case of Lunokhod-1, this system consisted of two transmitting cameras, electronic units and automation. Television cameras were designed on Vidicon-type transmitting tubes capable of long-term and adjustable image storage (3-20 s). The electromechanical shutter of the camera had a main shutter speed of 0.04 s with a possible change of shutter speed: - to a shorter one - 0.02 s and a longer one - up to 20 s. The camera had a wide-angle lens with F = 6.7 mm and D/F = 1:4. The viewing angle in the horizontal plane was 50°, and in the vertical plane - 38° (the viewing axis was inclined downward from the horizontal by 15°). The system provided television transmission at 3.2 speed; 5.7; 10.9; 21.1 s per frame.

The panoramic television camera system was intended to study surface properties and observe the Sun and Earth for navigation purposes. It produced clear images with minor geometric and brightness distortions and included four cameras with an optical-mechanical scanning device similar to those previously used during the Luna-9, -13 flights, but with better parameters. Two cameras located on different sides of the Lunokhod had horizontal panning axes and transmitted a circular panorama, which included images of the lunar sky and the surface near the wheels of the Lunokhod. The other two cameras provided panoramas (from different sides) that were close to horizontal, and each of them captured an angle of more than 180°. Information from this pair of cameras was used to study the surface relief and topographic characteristics of the study area.

Chemical express analysis of lunar soil was carried out using the X-ray spectrometric method (RIFMA equipment). The X-ray sources of the remote unit of this equipment contained H3 (hydrogen-3); ground radiation detectors were proportional counters. The RIFMA equipment made it possible to separately record X-ray radiation from rock-forming elements.

The study of the physical and mechanical properties of soil in its natural occurrence was carried out using special equipment PROP (patency assessment device), which included a cone-blade stamp for penetration and rotation in the soil, as well as a distance sensor (“ninth wheel”). The analysis also used data on the interaction of the Lunokhod chassis with the ground, photo panoramas, readings from roll and trim sensors, etc.

In addition to the listed equipment, Lunokhod-1 had a corner reflector for laser ranging of a mobile laboratory from Earth, equipment for recording charged particles and X-ray cosmic radiation.

The second Soviet self-propelled vehicle “Lunokhod-2” solved similar scientific problems and was similar to “Lunokhod-1” in its design. However, a number of improvements were made to its equipment and service systems: the capabilities of the device for chemical analysis of soil were expanded, the frequency of image transmission by course television cameras was increased, for a better overview of the area, one of them was raised on a bracket and moved forward. The equipment included instruments for magnetic measurements, astrophotometry and laser direction finding.

Multifunctional spacecraft of the 70s generation, designed for lunar exploration, provided scientists with new opportunities to study it. The era of laboratory geochemical research of substances delivered to Earth from various regions of the Moon has begun. As a result, our knowledge about it has reached a qualitatively new level - in less than ten years, in some respects, even more has become known about the Moon than about our home planet. This was largely due to the fact that although the Moon, its history and evolution, are more complex than previously thought, in geological and geochemical terms our natural satellite turned out to be much simpler than the Earth. It became clear that, despite the same age of both bodies, ~5 billion years, the main features of the external appearance of the Moon were formed in the first billion years after its formation. Thanks to laboratory research, the absolute age of numerous samples of lunar bedrock was determined, and the previously existing relative time sequence of lunar events was reliably linked to specific dates.

In the multi-colored, diverse and multi-layered mosaic of factual data about the Moon, connecting bridges have increasingly begun to appear, uniting initially unconnected fragments. Many of them, which previously did not fit side by side, began to fit well together, a general picture of the formation of the Moon began to be seen, changes in its face and internal structure with age, a picture of a gradual decrease in the activity of the processes operating on its surface and in its interior.

The first automatic "geologist" - "Luna-16" - landed on the Moon in the Sea of ​​Plenty, a typical marine area, the surface of which is composed of basaltic lavas. The soil taken consisted of rocks that filled the sea depression, emissions from large, nearby craters, and rocks mixed from the surrounding continental areas.

The Luna-20 AS descended to the mainland area with relative elevation differences of up to 1 km. This area is more ancient, apparently formed much earlier than the Sea of ​​Plenty.

The Sea of ​​Crises (“Luna-24”) has a number of specific features. Its deep depression is not filled with lava as abundantly as the neighboring “seas”. It is believed that this relatively “young” lava flowed to the surface about 3 billion years ago. At the center of the Sea of ​​Crisis is a mascon, a gravitational anomaly caused by a local concentration of mass. When planning the experiment, it was calculated that the sample would contain rocks bearing traces of the processes of the late stages of the magmatic evolution of the Moon. It was assumed that it contained rocks of a deep, subbasaltic layer, thrown to the surface during the formation of surrounding craters, for example, “Fahrenheit” or “Picart-X”. And it would be absolutely tempting to get a piece of the maskon substance.

This is how the outline of three successive experiments on drilling the lunar surface, extracting soil samples and studying it in terrestrial laboratories using the entire range of available means was roughly lined up.

Lunar soil, mined from various depths and delivered by Soviet automatic stations, has been and continues to be studied in laboratories in many countries around the world. The object of research is often individual soil particles, of which each gram of lunar material contains several billion. The particles represent crushed and mixed fragments of bedrock of the study area with a small contribution of particles from neighboring areas and meteorite matter, both with an unchanged and modified appearance by micrometeorite bombardment. Therefore, a soil sample of even a small volume has a very typical appearance for the rocks of a given region.

The lunar soil, delivered to Earth using the Luna-16 AS, is a granular powder that is easily formed and sticks together into separate lumps. Soil grain size increases with depth. On average, grains with a size of 0.1 mm predominate. The median grain size increases with depth from 0.07 to 1.2 µm.

In their composition, lunar samples are close to terrestrial basalts, but with an increased content of titanium and iron and a reduced amount of sodium and potassium. Lunar soil is well electrified, its particles stick to surfaces in contact with it. In the lunar regolith, two types of particles are clearly distinguished: some with an angular shape, externally similar to terrestrial crushed rocks; others (there are many more of them) have a rolled shape and show traces of melting and sintering, many of them in appearance resemble glass and metal drops.

The soil from the mainland region, delivered by the Luna-20 AS, differs significantly from the previous sample. It turned out to be much lighter, its basis was made up of fragments of crystalline rocks and minerals, and relatively few rounded and slagged (vitrified) particles were found. In contrast to the soil from the marine area, instead of basalt, the main ones here are anorthosites and their varieties - rocks of basic composition, but rich in feldspar.

The soil column from the Sea of ​​Crisis, delivered using the Luna-24 AS, is characterized by clearly visible layering; The layers differ in thickness, color and particle size. The color of the sample is uneven: the upper part is painted in a uniform gray color with a brown tint, the lower part is heterogeneous in color and consists of several layers of gray and a sharply distinguished layer of white material. In general, the soil is lighter than the sample from the Sea of ​​Plenty, but significantly darker than the soil returned by Luna 20. In addition, the soil from the Luna-24 station differs from the other two samples in its high content of relatively large fragments. The sample is widely represented by fragments of igneous rocks, with gabbro-type rocks predominating among them. Glass spherical particles are found only in the upper part of the column, but even there they are few. They make up slightly more than 1% of the total number of particles.

Interestingly, dark opaque glasses were found in the soil sample from the Sea of ​​Crisis, which were porous, angular fragments of irregular shape. The bulk of the particles have a matte rough surface. Such debris is not found in samples delivered to Earth using the Luna-16 and Luna-20 AS. The origin of these glasses is not entirely clear; some of them are, in all likelihood, volcanogenic in nature.

Mobile automatic scientific laboratories "Lunokhod" were intended to conduct long-term complex scientific and scientific-technical research on the surface of the Moon while moving the self-propelled vehicle over significant distances from the landing site. The first apparatus of this type, Lunokhod-1, “operated” in the Mare Monsim, a typically “sea” section of the lunar surface. The second is Lunokhod-2 in the eastern outskirts of the Sea of ​​Serenity (landing site - Lemonier crater).

As a result of tectonic processes, this crater was partially destroyed. Its bottom turned into a “bay”, and the preserved part of the shaft formed a ledge on the border of the Sea of ​​​​Clarity and the Taurus mountain range. To the south of the landing site, the “marine” surface of the crater turns into a hilly plain - the pre-continental area. In the coastal part of the crater there is a tectonic fault that stretches from north to south for almost two dozen kilometers. The width of the fault is several hundred meters, the depth ranges from 40 to 80 m. This crack arose after flooding with lava, although it may be a renewal of an ancient tectonic fault, which can be traced further in the mainland region behind the crater rim.

The Lunokhod mobile laboratories were equipped with a similar set of instruments for studying the physical characteristics of the Moon, and their scientific tasks were largely similar. The research program included: studying the geological and morphological characteristics of the area and its topography, analyzing the chemical composition of the soil along the route, determining the physical and mechanical properties of the surface and conducting laser ranging of the Moon. In addition, the Lunokhod-l program included experiments on recording solar and galactic X-rays and cosmic rays. Lunokhod-2, in turn, was equipped with instruments for magnetic measurements, astrophotometry and laser direction finding.

The study of the mechanical properties of the surface layer of lunar soil was based on determining the strength and deformation characteristics of regolith in its natural occurrence. In this case, it was assumed: to obtain, using special equipment, information about the load-bearing capacity of the soil, its compactability and resistance to rotational shear; study the interaction of the chassis with the soil - to assess the properties of the surface material along the entire route; carry out an analysis of television images that make it possible to identify features of the soil structure and its structure based on the depth of the Lunokhod ruts and the nature of soil deformation under the influence of their wheels.

The results obtained with the help of Lunokhod-1 showed that the bearing capacity of the regolith at different points on the surface varied over a fairly wide range and in most cases amounted to 0.34 kg/sq. cm. Rotational shear resistance averaged about 0.048 kg/sq.m. cm. The bearing capacity of the uppermost dust layer was in the range of 0.02-0.03 kg/sq. cm. The greatest resistance to the penetration of equipment into the ground was noted in areas not strewn with stones, the least - in the area of ​​​​the annular shafts of craters. The ability of lunar soil to be significantly compacted and strengthened upon repeated loading was discovered. When measuring the parameters of the soil lying at a depth of 8-10 cm and exposed during the Lunokhod maneuvers, higher mechanical properties were revealed: bearing capacity of about 1 kg/sq. cm, shear strength 0.06 kg/sq. cm.

To carry out magnetic measurements along the route and during stops, Lunokhod-2 had a three-component fluxgate magnetometer on board. Analysis of these measurements indicates the inhomogeneity of the magnetic field of the lunar surface: the component of the magnetic field parallel to the surface, during measurements along the Lunokhod route, varied from 5 to 60 gammas, magnetic anomalies characteristic of craters were discovered (in the area of ​​individual craters, field differences of up to 3 gammas were noted /m). Magnetic measurements carried out in the area of ​​the tectonic fault and the rim of the Lemonnier crater made it possible to assess the magnetization of the rocks dissected by the crack, as well as the continental rocks of the crater rim.

Geological and morphological studies of the areas through which the Lunokhods moved were aimed at obtaining data on the relief and identifying characteristic geological formations, establishing their relationship and evolution, and determining the features of the microrelief and constituent rocks.

Analysis of materials obtained in the Sea of ​​the Rains showed that the main form of microrelief in this area are craters. Craters up to 50 m in size were clearly visible in the images. Negative relief forms with a diameter of less than 10 cm and having specific features were identified in a special group. The craters in this area had a characteristic cup-shaped shape, their appearance varied from clear to blurred, according to which they were grouped into three morphological classes - A, B and C.

Class A craters typically had a clearly defined ridge or sharp boundary with the surrounding surface. The ratio of depth to diameter (H/D) for craters of this class lies in the range of 1/4-1/5. The steepness of the internal slopes in the upper part was 35–45°. Class B craters are smoother: the H/D ratio for them is about 1/8, the maximum steepness of the internal slopes rarely reaches 30°. Class C craters had the smallest relative depth (H/D = 1/14), the steepness of their slopes was 8-10°, and there were no clear boundaries.

All craters are located randomly on the surface, which is typical for landforms of exogenous origin. Some of the craters apparently formed as a result of secondary impact processes - falling fragments of low-strength rock at low speed. Rock fragments on the surface are a common element of the lunar landscape.

Geological and morphological studies also included studying the thickness and vertical section of the regolith layer, its structure and granulometric composition. Data from the analysis of the geological situation lead to the conclusion that the surface rocks of the Sea of ​​the Mons crystallized after their melting in the period 3.2–3.7 billion years ago. The bulk of the craters are of impact-explosive origin, and the morphological differences are associated with their evolution. The coarse material apparently resulted from the crushing of the bedrock during the formation of craters.

The thickness of the regolith ranges from 2–6 m, and in some cases can reach 50 m. When moving from young to old craters, the microstructure of the upper layer of regolith naturally changes from rubble to lumpy and cellular-lumpy, and the granulometric composition becomes finer. Directly under the regolith layer, apparently, there are rocks of the breccia type of basaltic composition, below - basalts.

During their work, Soviet self-propelled vehicles controlled from the Earth covered a route about 50,000 m long, transmitted more than 300 panoramas and 100,000 photographs, and conducted multiple studies of the physical, mechanical and chemical properties of the soil.

ON THE FLIGHT ROUTE EARTH - MOON - EARTH

One of the important stages in the study of the Moon in the Soviet Union was the use of AS “Zond” series, intended for testing space technology systems in real flight conditions, methods and means used during long interplanetary flights, as well as for conducting experiments in outer space.

The program of the Zond-3 AS, launched on a long flight in a heliocentric orbit, in addition to other experiments, included photographing the Moon, including those areas of its far side that were not covered by photography during the flight of the Luna-3 station. On board the Zond-3 AS, a photo-television complex was tested and developed, designed to take photographs of planets and transmit information from distances of up to hundreds of millions of kilometers. When transmitting information, the station was oriented in space in such a way that its parabolic antenna was aimed at the Earth with high accuracy.

The lunar photographing program involved overlapping images of still unknown areas with photographs of areas already photographed by Luna 3, as well as areas that could be observed from Earth. This provided a good cartographic reference for new photographic information. The Moon was photographed from distances from 11.6 to 10 thousand km. This distance made it possible to photograph large areas and obtain fairly large-scale images. The photo session lasted about 1 hour. At the same time, the position of the station relative to the Moon changed in longitude by 60° and in latitude by 12°. Thus, each section of the unexplored territory was photographed from different angles, which significantly increased the information content of the image.

Interestingly, along with in-flight photography, the spectral characteristics of the lunar surface were recorded in the infrared, visible and ultraviolet ranges. The optical axes of the devices were located parallel to the camera axis. Photographic images and spectral characteristics of the same areas of the surface, studied together, provided more opportunities for a comprehensive study of the physical properties of the lunar surface and their relationship with landforms.

The automatic probes “Zond-5, -6, -7, -8” were intended to conduct research on the Earth-Moon-Earth flight path, including photographing the Moon and Earth and delivering experimental materials to Earth (see Appendix). By the time the first of these devices was launched, 14 Soviet automatic stations had visited the Moon and its surface. Messengers from Earth went on a flight to the nearest planets - our neighbors in the solar system. With their help, methods for conducting scientific and technical experiments at large distances from the Earth with the transmission of information about the experiments carried out via radio channels were tested and fine-tuned. These methods of space research have shown their high efficiency in practice. However, over time, it became increasingly obvious that many very important scientific and technical problems associated with the study of celestial bodies and remote areas of space could not be solved with the help of devices that had left the Earth forever. It was necessary to create devices capable of not only “breaking the chains of gravity,” but also returning to the “embraces of our native planet.”

The development of fundamental sciences about the Universe, for example planetology, required the study of the substance of large celestial bodies, its chemical composition, rock-forming minerals and other characteristics in earthly laboratories using a full range of comprehensive fine analysis tools. It was also important to obtain photographs of the surfaces of space objects without interference and distortion introduced by the processing system on board and when transmitting information via radio channels over long distances.

Actively developing space medicine and biology also presented their demands. After all, in order to fully identify the consequences of the effects of space flight factors on living organisms, it is necessary to return them to Earth. Finally, this also required research into the impact of the space environment on structural materials and equipment in order to use this knowledge in the future to create new, more advanced space technology.

The problem of returning vehicles to Earth after performing near-Earth orbital flights has already been successfully solved. Human space flights have become commonplace. New automatic stations were to master the return to Earth from the flight route to the Moon, after entering the atmosphere at the second escape velocity. This was the task of tomorrow for world cosmonautics. It was at this point that the possibility of human flights to the Moon, and in the future to the planets, was tested in practice.

The Zond-5 AS consisted of two main parts: the instrument compartment and the descent module. The instrument compartment contained equipment for control systems, orientation and stabilization, thermal control and power supply, radio complex units, as well as a corrective propulsion system. Optical sensors of the orientation system, solar panels and radio antennas were mounted on the compartment.

The return vehicle was used to install scientific equipment, conduct experiments on the flight route to the Moon and during return to Earth. It had a segmental-conical shape, which, with the center of gravity shifted from the axis of symmetry, made it possible, using a special control system, to perform a descent to Earth not only along a ballistic trajectory, but also a controlled descent, and the landing site varied widely.

Rice. 10. Flight diagram of AS “Zond-5”

The scientific equipment of the AS included instruments for recording charged particles and micrometeors, and photographic equipment. During the flight, the influence of space flight conditions on living organisms and other biological objects located in a special compartment of the reentry vehicle was studied.

The AS was launched onto the flight path from the intermediate orbit of an artificial Earth satellite (Fig. 10). To form the required trajectory around the Moon, at the moment when the station was at a distance of 325,000 km from the Earth, the propulsion system was turned on, which informed the AS the required value of the correction impulse.

After flying around the Moon, at a distance of 143,000 km from the Earth, a second trajectory correction was carried out, ensuring that the station entered the Earth’s atmosphere in a given area with the calculated descent angle (the landing site was in the Indian Ocean). The descent in the atmosphere was carried out along a ballistic trajectory.

In this flight, for the first time in the history of astronautics, the problem of a soft landing on Earth of a spacecraft returning from a flyby of the Moon, entering the atmosphere at the second escape velocity, was solved.

The remaining stations in this series were similar in design to the Zond-5 AS, although their program varied. Thus, the return of the Zond-6 AS descent vehicle to Earth was carried out along a controlled trajectory, consisting of a section of the first dive into the atmosphere, an intermediate extra-atmospheric flight, a section of the second dive and descent to the surface. The Zond-7 AS program included testing of the on-board computer, high-precision orientation system, and radiation protection equipment for spacecraft. During the flight of the Zond-8 AS, further development of the technique for returning the vehicles to Earth was carried out; entry into the atmosphere after flying around the Moon was made from the northern hemisphere of the Earth.

PROSPECTS FOR STUDYING AND DEVELOPING THE MOON

The past twenty years of rapid development of selenology, caused by the use of space means, have given scientists a wealth of experimental material. Much about the structure of the Moon is known today. Much remains to be learned, developed and clarified, much needs to be rethought using the already existing array of scientific information. The process of cognition is continuous. It is necessary to move forward, to obtain new facts, to generalize them, to move further along the endless road of revealing the secrets of the Universe.

What is the future path of studying the Moon? In what directions will its development go?

Without pretending to provide an exhaustive coverage, we will try to make several general assumptions and consider some particular aspects of this complex picture.

The Moon as an object for the application of astronautics is of interest from several points of view.

Firstly, experiments will be continued to study the nature of the Moon and obtain more complete and detailed information about its structure. There are still many “white spots” on the Moon, and this applies primarily to the polar regions and the far side, not visible from Earth. These areas require geological and geochemical research. Very little is known about heat flows from the lunar interior and their variations in different regions. The structure of the lunar interior, studied by seismic methods, is not known accurately enough; there are different points of view on the presence, size and physical state of the lunar core. These data are necessary for studying the general patterns inherent in the structure of large celestial bodies of the Solar System, including the Earth.

Currently, it seems extremely interesting to study the deep structure of lunar regolith in characteristic areas of the Moon and especially on the surface of the hemisphere not visible from the Earth. Drill cores obtained to depths of several tens or even hundreds of meters are the most informative type of lunar samples, as they contain fragments of local and introduced rocks, both primary and reworked by meteorite bombardment. The sequence and nature of the arrangement of individual layers make it possible to establish the history of their deposition, the degree of processing by exogenous factors, the degree of mixing, the time spent on the surface, the intensity of bombardment by micrometeorites, the degree of irradiation by solar and galactic cosmic rays.

The second interesting aspect of the exploration of the Moon is the possibility of using its surface to accommodate various scientific equipment in order to conduct a wide range of astronomical and astrophysical experiments. The absence of an atmosphere on the Moon creates almost ideal conditions for observing and studying the planets of the Solar System, stars, nebulae and other galaxies. Under these conditions, the resolution of a telescope with a mirror diameter of 1 m will be equivalent to the resolution of a ground-based instrument with a mirror with a diameter of 6 m. In addition, the absence of an atmosphere makes it possible to conduct research using almost the entire range of the electromagnetic spectrum, which will allow us in the future to dramatically expand our knowledge of our own solar system. system, and at a new level approach the resolution of the mysteries hidden in such exotic astronomical objects as pulsars, quasars, neutron stars and black holes, and study the grandiose processes occurring in the bowels of galaxies.

For radio astronomy observations, the Moon presents no less advantages than for optical ones. A modern radio telescope is, first of all, an antenna, the large dimensions of which determine all the operating characteristics of the radio telescope. On Earth, due to the enormous weight of the metal structures of the antenna and the requirements for the precision of its rotation mechanisms, the practical limit of the sensitivity and resolution of these structures has already been reached. The gravity on the Moon, reduced by six times, largely eliminates this problem. In addition, in terrestrial conditions, the work of radio astronomers is hampered by the abundance of radio interference due to electrical discharges in the atmosphere and the multitude of radio transmitting and electrical devices that create an intense background of radio interference. The location of the radio telescope on the far side of the Moon radically solves this issue.

Another attractive prospect for radio astronomy is the possibility of using two radio telescopes: one on Earth, the other on the Moon, as a radio interferometer - a system that can dramatically increase resolution. The use of this technique under terrestrial conditions made it possible to obtain radio images of large features of the surface of Venus, inaccessible for remote optical observations due to its thick cloud layer. Under terrestrial conditions, the use of the principle of radio interferometry is limited by the diameter of the globe. Installing a radio telescope on the Moon will increase the base - the distance between two radio telescopes - to 384,000 km and dramatically increase the resolution of the entire system.

Despite the fact that the theory of relativity has long been generally accepted, the question of experimental confirmation and clarification of the numerical coefficients underlying it has not ceased to be relevant. One aspect of this refinement is the registration of the magnitude of the deviation of light rays from distant stars under the influence of the gravitational field of the Sun. Under terrestrial conditions, such measurements are possible only during total solar eclipses, and their accuracy is limited by the phenomena of scattering and refraction of light in the atmosphere. Using a lunar telescope equipped with a screen covering the luminous disk of the Sun, such measurements can be carried out at any time.

The list of studies that can be conveniently carried out from the surface of the Moon can be further expanded. However, before we finish with this issue and move on to another topic, it should be emphasized that studying our home planet, the Earth, from the Moon is very promising. The advantages of studying the earth's surface from long distances, which allows it to be perceived in a generalized form, became obvious after the first global photographs of the Earth were obtained using spacecraft. It is well known how much information global images can give us about the geological structure, the general picture of atmospheric circulation, ice cover, pollution of the atmosphere and oceans of the Earth as a whole.

With the next step in changing the scale of observations - when observing the Earth's surface from the Moon, new discoveries should be expected. The organization of observatories on the Moon for constant observation of the Earth makes it possible to conduct a systematic operational analysis of the meteorological situation on the globe as a whole, and to effectively study the processes occurring in the atmosphere and their connection with solar activity. When registering thermal radiation with wavelengths of 3.6-14.7 microns, you can almost instantly obtain a picture of the temperature distribution in the upper layers of the troposphere in the hemisphere as a whole, and when registering radiation in the range of 9.4–9.8 microns - the temperature of the earth's ozone layer atmosphere.

Active probing of the Earth's atmosphere with radio and light location at various wavelengths will make it possible to obtain a complete picture of the distribution of rain and snowfall zones, their sizes and intensity, and to conduct ice reconnaissance immediately on a hemispheric scale. Color-zonal photography, which has already shown its effectiveness during the work of crews on board orbital stations, and during observations from the Moon, will be useful to various specialists for the study and rational use of earth's resources and environmental protection.

The solution to new, promising problems in the study and exploration of the Moon is inextricably linked with the development of all astronautics and is largely determined by the improvement of space technology. The accumulated scientific and technical potential is a reliable foundation for the deployment of the entire necessary range of work in this direction. Automatic stations for various purposes, artificial satellites of the Moon, automatic devices for taking soil samples and delivering them to Earth, self-propelled mobile laboratories, which have made a great contribution to the successes of selenology, will faithfully serve science in the future. Their constant improvement, expansion of ranges, increase in autonomy, service life and reliability will allow them to continue to play a significant role in the exploration of the Moon.

As one of the possible options for using automatic devices in future exploration of the Moon, one can imagine a system that includes self-propelled vehicles, similar to the already familiar Lunokhods, as well as stations like Luna-16. Mobile self-propelled vehicles, moving over a large area, will be able to carry out scientific measurements and take soil samples, and devices such as the Luna-16 station will be able to ensure the delivery of materials, experiments and lunar soil to Earth.

Experiments and research on the Moon can be carried out using various methods. For example, it is possible to create research sites equipped with automatic equipment in various areas of the Moon. In particular, the polar regions of the Moon are very promising areas for organizing test sites there. Currently, they are the least studied compared to other areas, which significantly increases the interest in them from scientists. However, besides this, they are interesting for a number of other reasons. So. Constant illumination by the Sun of the polar regions is very important both for the energy supply of scientific and technical complexes and for conducting some selenophysical experiments. In particular, the absence of significant temperature changes caused by the change of day and night in these areas is very convenient for measuring heat flows from the lunar interior. It is also important that the observation of various celestial objects from the polar regions allows you to keep them in the field of view of observation instruments for an unlimited time.

It should be noted that the equipment of research sites on the Moon must be able to operate for a long time according to a complex and flexible program, operate reliably and efficiently in extreme conditions of outer space, when exposed to sudden temperature changes, micrometeorite bombardment, irradiation by solar wind and cosmic rays.

The equipment of such a test site can record seismic vibrations of the Moon, heat flow from its interior, the composition of gases released from the interior of the Moon, the composition and energy of the solar wind, the mass, energy and direction of movement of micrometeorite and dust particles, the composition and energy of galactic cosmic rays. Delivery of various scientific instruments to the test site can be carried out automatically. Such a complex could function without human intervention. An option is possible when the test site is periodically visited by specialists who carry out repairs, replace equipment, and pick up and deliver information material to Earth.

The creation of research sites can technically be accomplished in the near future. The current state of cosmonautics and scientific instrument making allows us to hope for this. In a slightly longer term, I would like to imagine the possible combination of such a test site with an inhabited base where a team of research scientists works. The creation of inhabited scientific bases on the Moon, generally speaking, is a matter of the distant future, but experts are already thinking about various options for their design and equipment.

According to one of the proposed projects, the living space of such a base is a hemispherical or cylindrical shell made of multilayer elastic material reinforced with steel threads. The shell maintains its shape under the influence of internal pressure. The base room is slightly recessed below the surface and is protected from temperature changes and micrometeorite bombardment by a layer of soil (a layer of 15–20 cm is sufficient for protection from meteorites 1–2 cm in size).

Initially, 2–3 people can work at the base; in the future, the staff may increase. The duration of stay at the base will reach several months. For astronauts to work effectively, they must have vehicles for various purposes: from single or double lunar rovers with a carrying capacity of 300–400 kg with a cruising life of 30–40 km to heavy transport devices with a cruising range of up to 500 km, providing the ability to conduct scientific work for 15 days.

The joint use of a stationary lunar base and an orbital complex is very promising for lunar exploration. In this case, it seems possible to deliver the landing compartment with astronauts to any part of the lunar surface located in the orbital plane of an inhabited satellite. A characteristic feature of such a project is that the crew, while at the orbital station, can wait a long time for the astronauts to land on the Moon.

For quite some time, the requirements for operating the rocket transport system between the Moon and Earth will remain complex. Apparently, the most energy-efficient way to transport cargo between the lunar and near-Earth orbital stations will be the use of electric jet engines powered by solar energy and relatively low thrust, ensuring an Earth-Moon flight in 30–90 days. Delivery of cargo and people from Earth to low-Earth orbit will be carried out by multiple-use spacecraft running on chemical fuel. For flights from the Moon to the lunar orbital station and back, it may be rational to build on the surface of the Moon an electromagnetic catapult (powered by solar energy), used both for launching vehicles into lunar orbit and for their soft landing on the surface.

There is one more direction in lunar exploration, which may be worth discussing separately. We are talking about obtaining structural materials and developing minerals for use in creating scientific bases, and in a somewhat more distant future - in organizing technological production on the lunar surface and building satellite solar power plants.

Rice. 11. One of the options for the trajectory of transporting lunar soil to a space processing plant

Currently, the issue of the feasibility of creating large energy satellites in near-Earth orbits equipped with equipment for converting solar energy into electrical energy with its subsequent transmission to Earth (in the form of microwave energy) is being widely discussed in the press. The solution to this technical problem will probably free humanity from the energy crisis for a very long time and will facilitate the protection of the human environment from pollution. These projects, at first glance, far from lunar topics, unexpectedly turned out to be included in the range of problems associated with the exploration of the Moon.

The fact is that the energy complexes under consideration are conveniently located in the vicinity of the Moon, at the so-called “triangular libration points.” An artificial Earth satellite located near one of these points has an extremely stable orbital motion. In addition, delivery from the Moon of structural materials that make up the bulk of the satellite, or raw materials for their production, requires 20 times less energy than delivering them from Earth. The final assessment leads to the conclusion that the construction of such systems can be profitable only if raw materials are delivered from the surface of the Moon.

In Fig. Figure 11 shows a diagram of one of the options for transporting cargo from the Moon to an energy satellite. A special mechanism powered by electricity accelerates containers with cargo to a speed of 2.33-2.34 km/s, sufficient to escape the sphere of gravity of the Moon. Then the containers fly along a ballistic trajectory and fall into a catcher, which is a cone with a diameter of 100 m at the base. The “catcher” cone must have an onboard propulsion system to maintain the desired position in orbit, as well as to transport containers with cargo to the satellite.

If we consider lunar soil as a raw material for processing, we can easily see that it is easiest to isolate metallic iron from it. Particles that can be separated using weak magnetic fields account for 0.15-0.2% of the total weight of the soil. They contain about 5% nickel and 0.2% cobalt. A conventional metallurgical process must be used to completely recover the iron, aluminum, silicon, magnesium and possibly titanium, chromium, manganese, as well as the oxygen that is produced as a by-product.

One of the possible schemes of such a process is shown in Fig. 12. It all starts with grinding the soil to a maximum particle size of 200 microns (vibrating mills can be used for this). Next, it is sent as a gas stream to the firing furnace, and on the way to the furnace, ferrosilicon, crushed to particles 50 microns in size, is added to the soil. Ferrosilicon is necessary for the reduction of iron, but, in addition, it is itself an intermediate product at other, subsequent stages of the metallurgical process.

At a temperature of 1300 °C, silicon will diffuse out of the ferrosilicon particles and iron will be reduced. The product of this process is a silicate melt with iron particles suspended in it. After cooling and grinding this mixture, the iron is recovered using magnetic separation, and the low-iron silicate enters the main reactor.

Rice. 12. One of the variants of the technological scheme for obtaining structural metals from lunar soil. Among the technological devices, it includes: a furnace for distilling aluminum from the melt at a temperature of 2300 °C (II), a furnace for distilling calcium, magnesium, aluminum, silicon and carbon monoxide (III), a reactor for the reduction of metals with carbon (IV). The following processes are used: separation iron (2), fusion of iron and silicon at a temperature of 1500 °C (3), distillation of magnesium at a temperature of 1200 °C (4), condensation and filtration (5), electrolysis of water (6), separation of solid and gaseous electrolysis products (7 ), diffusion of iron from silicates (I). A centrifuge furnace is also required to separate iron and slags (1)

In the main reactor, which can be imagined as a furnace rotating around a longitudinal axis (for gravitational separation of the resulting alloy of metals, slag and gases), thermal reduction of metals occurs. After carbon is added to the silicate entering the reactor and when the mixture is heated to 2300 °C, chemical reactions of the reducing type occur, proceeding with the release of heat.

At this stage of the metallurgical process, the resulting silicon-aluminum alloy is separated from the slag and gaseous products and enters a distiller, where aluminum and silicon are separated. Carbon monoxide, calcium, magnesium and partially aluminum and silicon vapors undergo further separation. Carbon monoxide, for example, can combine with hydrogen to form water, methane and some other hydrocarbons. This reaction has long been used in industry and is well studied. Iron oxide can be used as a catalyst. Methane as well as hydrogen are dried in a condenser to separate the water. Water is decomposed by electrolysis into oxygen and hydrogen. Oxygen is released into the finished product, and hydrogen is returned to the reactor.

The metallurgical process considered as an example is quite suitable for lunar conditions in terms of the energy consumption required for this equipment and its practical efficiency. For its implementation, it requires a minimum of substances delivered from the Earth and gives a good yield per unit mass of equipment. Substances of “non-lunar” origin in the technological cycle will be only carbon and hydrogen, which are practically not consumed, but are used in a closed cycle.

In addition to obtaining metals and other chemicals from lunar soil, one can imagine other possibilities for processing this soil into structural materials, such as glass. The raw material for glass production can be plagioclase from continental regolith, which is almost pure CaAl2Si2O8 with 0.5% NaO2 and a fraction of a percent FeO. Compared to terrestrial glass, glass made from lunar soil should be stronger and withstand longer mechanical loads without destruction, since due to the lack of water in the lunar rocks, the surface of the glass should have fewer defects that reduce its strength.

Using lunar soil, it is possible to carry out a process such as basalt casting, which is widely used in the manufacture of hollow bricks, building blocks, pipes with a diameter of 3-10 cm and a length of 1-1.5 m, which are highly resistant to acids and alkalis. The strength of the products of this casting from lunar rocks can reach 10,000-12,000 kg/sq.m. when compressed. cm, and when stretched -500-1100 kg/sq. cm.

Sintered materials can be used to manufacture structural elements with low thermal conductivity, as well as filters. Based on the totality of characteristics, the most favorable conditions for sintering lunar soil particles are heating them to temperatures of 800–900 °C with exposure in an oven from several seconds to tens of minutes and subsequent rapid cooling at a rate of 0.1–5 °C/min.

Rough calculations show that in some cases it is more cost-effective to process lunar material into structural materials in outer space rather than on the Moon. When organizing a technological cycle on the surface of the Moon, it is not always possible to provide continuous illumination by solar rays of devices that convert light into electricity, while in outer space this does not pose a difficult problem. If we consider that transporting cargo from the lunar surface to space requires 5 times less energy than processing it, then the final energy cost of production in outer space is 8 times less than on the Moon.

It is likely that the energy satellites of the future, which were discussed above, are more correctly imagined as some industrial-energy complexes with large production capabilities.

So, since the most ancient times of human history, the Moon has always been an object of admiration and keen interest. However, at different periods in the development of our civilization, the Moon had different effects on the feelings and minds of people. The romantic period of perception of the Moon was replaced at one time by a rationalistic one. Following the poets, scientists turned their inquisitive gaze to it, and then the time came for people of practical intelligence.

A huge role in bringing the Moon into the sphere of practical interests was played by the impressive successes of astronautics, which revolutionized our ideas about the place of humanity in outer space and brought the vast expanses of the Universe closer to us. The efficient operation of Soviet spacecraft in space largely determined these successes.

The Earth's "seventh continent," as the Moon is sometimes called, is increasingly attracting the attention of engineers and economists who are considering various options for using its natural resources. And let the development of the lunar subsoil and the creation of scientific bases not be the primary task of today. All the same, someday humanity, through joint efforts, will begin work on the exploration of the celestial body closest to us. And then people will remember with gratitude the first spacecraft, which paved the way for the practical exploration of the natural satellite of our home planet.

APPLICATION

Information about Soviet vehicles for lunar exploration

№	Device name	Launch date (Moscow time)	Flight Basics
Flights of AS "Luna"
1.	"Luna-1"	2. I.1959	The first spacecraft in history directed towards a celestial body. For the first time, the second escape velocity necessary for interplanetary flights has been achieved.
2.	"Luna-2"	12.IX.1959	For the first time in the history of astronautics, a flight was made to another celestial body.
3.	"Luna-3"	4.X.1959	The first photographs of the far side of the Moon have been obtained. Based on the photographic results, the first maps and atlas of the far side of the Moon were compiled.
4.	"Luna-4"	2.IV.1963	Testing of space technology for the exploration and development of the Moon, 6.IV.I963. The AS passed a distance of 8500 km from the lunar surface.
5.	"Luna-5"	9.V.1965	Testing a soft landing system on the Moon. On May 12, 1965, the station reached the surface of the Moon in the Sea of ​​Clouds region.
6.	"Luna-6"	8.VI.1965	Testing and testing of systems, AS, its celestial orientation, radio control, autonomous control, as well as radio control of the flight path.
7.	"Luna-7"	4.X.1965	Testing a soft landing system on the Moon. On October 8, 1965, the station reached the surface of the Moon in the region of the Ocean of Storms, west of the Kepler crater.
8.	"Luna-8"	3.XII.1965	Comprehensive testing of station systems at all stages of flight and landing. The station reached the surface at a point with selenocentric coordinates: 9°8 s. latitude, 63°18w. d.
9.	"Luna-9"	31.I.1966	The first spacecraft to make a soft landing on a celestial body and transmit scientific information, including a series of panoramic images from its surface. The lunar landing occurred on January 3, 1966 in the area of ​​the Ocean of Storms at a point with coordinates: 7°8 N. latitude, 64°22w. d.
10.	"Luna-10"	31.III.I966	The first artificial satellite of the Moon. Launched into orbit on April 3, 1966. Orbital parameters: maximum distance from the surface (apopulations) about 1000 km, minimum distance (periselations) about 350 km, inclination to the lunar equator - 72°, orbital period about 3 hours.
11.	"Luna-11"	24.VIII.1966	Continuation and development of experiments begun by the Luna-10 station. The second Soviet satellite of the Moon was launched into a lunar orbit with the following parameters: apopulation - 1200 km, periselation - 160 km, inclination - 27°, orbital period about 3 hours.
12.	"Luna-12"	22. X. 1966	The third Soviet artificial satellite of the Moon. Orbital parameters: apopulation - 1740 km, periseleny - 100 km, orbital period 3 hours 25 minutes. The station is equipped with a photo-television device. Photographing altitudes range from 100 to 340 km.
13.	"Luna-13"	24.XII.I966	Soft landing on the Moon. Landing site coordinates: 18°52 s. latitude, 62°3w. d. The station is equipped with: a television device for transmitting images of the surface, instruments for obtaining characteristics of the physical and mechanical properties of the soil at the landing site.
14.	"Luna-14"	7.IV.1968	The study of the Moon and outer space from lunar orbit was carried out.
15.	"Luna-15"	13.VII.I969	Exploration of the Moon and the space environment, testing of new structural elements and on-board systems. On 17.VII.I969 it was launched into orbit as an artificial satellite of the Moon. 21.VII.I969 was transferred to the descent trajectory and reached the lunar surface.
16.	"Luna-16"	12.IX.1970	Delivery of a sample of lunar soil to Earth. For the first time in astronautics, soil was delivered by an automatic device. A soft landing was made on 20.IX.1970 in the Sea of ​​Plenty area, at a point with coordinates: 0°41 south. la., 56°18 E. d. Drilling was carried out to a depth of up to 350 mm, sample weight is about 100 g.
17.	"Luna-17"	10.XI.1970	Delivery to the Moon of the first mobile scientific laboratory in the history of astronautics (Lunokhod-1), controlled from the Earth. The landing on the Moon took place on November 17. 1970 in the Sea of ​​Rains area. Landing site coordinates: 38° 17 s. latitude, 35°w. d. 4.X. 1971 Lunokhod-1 completed the research program.
18.	"Luna-18"	2.IX.1971	Exploration of the Moon and outer space, testing of structures and on-board systems, testing methods of autonomous lunar navigation and ensuring the necessary accuracy of landing on the Moon. The station reached the surface of the Moon in the region of the Sea of ​​Plenty at the point with the coordinates of the landing site: 3°34 s. la., 56°30 E. d.
19.	"Luna-19"	28.IX.I971	Studying the gravitational field of the Moon, conducting television filming of the surface, studying charged particles and magnetic fields in the vicinity of the Moon, and the density of the meteor shower. The station was placed into a circular orbit of an artificial satellite of the Moon with the following parameters: height above the surface - 140 km, inclination - 40°35, orbital period - 2 hours 1 min 45 s.
20.	"Luna-20"	14.2.1972	Delivery to Earth of soil samples from the continental region of the lunar surface. Landing site coordinates: 3°32 s. latitude, 56°33 e. d. Drilling was carried out to a depth of about 300 mm; sample weight 50 g.
21.	"Luna-21"	8. I.1973	Delivery of the self-propelled scientific laboratory "Lunokhod-2" to the lunar surface. The landing took place on the eastern edge of the Sea of ​​Clarity at a point with coordinates: 25°51 N. latitude, 30°27 e. d.
22.	"Luna-22"	29.V.I974	Conducting television filming of the lunar surface, studying charged particles, magnetic fields, micrometeoric matter in the lunar space. Initially, the station was placed into a circular selenocentric orbit with the following parameters: altitude above the surface - 220 km, inclination - 19°35, orbital period - 2 hours 10 minutes.
23.	"Luna-23"	28. X. 1974	Launched with the aim of delivering a sample of lunar rock to Earth, testing new design elements and equipment for automatic lunar stations. The landing took place in the southern part of the Sea of ​​Crisis. Due to damage to the soil sampling device during planting, soil sampling operations were not carried out. The station's work program has been partially completed.
24.	"Luna-24"	9.VIII.1976	Carrying out deep drilling on the surface of the Moon and delivering soil samples to Earth. The landing took place in the south-eastern part of the Sea of ​​Crisis at a point with coordinates: 12°45 N. latitude, 62°12 e. d. The new drilling device made it possible to drill to a depth of about two meters. The weight of the delivered sample is 170 g.
Flights of AS "Zond"
25.	"Zond-1"	2.IV.1964	Development of space technology for long-term interplanetary flights. The station was launched into flight along a heliocentric trajectory from the orbit of an artificial Earth satellite. Communication sessions were carried out with the station, the operability and functioning of on-board systems were checked, and the movement trajectory was corrected.
26.	"Zond-2"	30.XI. 1964	Testing the design and systems of the AS under conditions of long-term space flight, studying the interplanetary environment during the flight towards Mapca. Testing of an orientation system using electrojet plasma engines as control elements.
27.	"Zond-3"	18.VII.I965	Photographing areas of the far side of the Moon not covered by the Luna-3 station.
28.	"Zond-4"	2.III. 1968	Space exploration, testing of new units and systems.
29.	"Zond-5"	15.IX.1968	Testing the design of spacecraft, photographing the Earth from space. Study of physical conditions on the Earth-Moon-Earth route and their impact on living organisms.
30.	"Zond-6"	10.XI.I968	Conducting scientific and technical experiments on the Earth-Moon-Earth flight path, photographing the Moon and Earth from space. The movement of the AS in the atmosphere when returning to Earth was carried out along a controlled descent trajectory using the lifting force of the return vehicle. Zond 6 orbited the Moon.
31.	"Zond-7"	8.VIII.I969	Studying the physical characteristics of outer space on the flight route to the Moon and when returning to Earth, photographing the Earth and the Moon from various distances, testing a control system from an on-board computer, a high-precision orientation system, and radiation protection equipment for spacecraft. The descent in the atmosphere took place using the lifting force of the re-entry vehicle. Zond 7 flew around the Moon.
32.	"Zond-8"	20. X. 1970	Flying around the Moon, conducting scientific research on the flight path, photographing the Earth and the Moon from various distances, testing the design of spacecraft. The station entered the Earth's atmosphere from the Northern Hemisphere.