Description of the properties of rocky soil. Technological novelty of the project

The work obtained a solution to the problem of a hard landing of the Mars-6 descent module, which during its mission in 1973 crashed on the surface of the Red Planet. To clarify the circumstances of the hard landing, a numerical simulation of the vehicle’s impact on the Martian soil was performed using the LS-DYNA software system. The modeling results are compared with satellite imagery data.

Authors: I.A. Dolgov, Yu.V. Novozhilov, D.S. Mikhalyuk - JSC "CIFRA".

Consultant: V.Yu. Egorov - LLC "NPP DAURIYA"

"Mars-6" - automatic interplanetary station, which was launched in the USSR in 1973. The spacecraft consisted of a space transfer unit and a landing module - a descent vehicle. The Mars-6 orbital station remained in the asteroid belt, and during the descent stage the descent vehicle managed to deploy a parachute and analyze the composition of the atmosphere, but at the moment the braking rocket engines were turned on, communication with it was interrupted. To study the causes and consequences of the accident, the crash site is studied using satellite photography analysis methods. Today, the search for Mars-6 is possible thanks to the American MRO satellite, which films the surface of Mars, with detail up to 26 cm. It was in this way that in 2013, Vitaly Egorov, who worked as part of a group of enthusiasts, found the Mars apparatus at the bottom of the giant Ptolemy crater -3" .

Due to the fact that the landing of Mars-6 was most likely an emergency, elements of the apparatus and parachute may not be visible clearly enough even on a satellite photograph with great detail. The device after colliding with the surface of the planet on high speed could leave a crater and bounce a significant distance. For a more detailed analysis of the consequences of a hard landing, it is necessary to use modern numerical modeling methods, which make it possible to directly simulate the process of the descent vehicle impacting the surface of the planet. Based on the results of such a calculation, it is possible to determine the size of the crater that can be formed when the lander impacts at a given speed, as well as the distance to which the lander flies off after initially touching the surface of the planet. Thus, knowing the values ​​of these parameters, it is possible to reduce the number of search zones on satellite imagery and determine the location of the descent vehicle on the surface of the planet.

To predict the size of the impact crater during a hard landing of the Mars-6 spacecraft, the following tasks were set and solved:

1. Creation of a computational model of the descent vehicle with the most reliable mass-stiffness characteristics;
2. Creation of a computational model of the soil of Mars at the landing site, taking into account nonlinear physical and mechanical properties soil;
3. Conducting a multivariate study of the collision of the Mars-6 apparatus with the soil of Mars at different speeds and angles of incidence;
4. Comparison of the dimensions of the resulting crater in numerical modeling with the dimensions of the crater using data from satellite imagery.

Composition and results of the Mars-6 mission

In 1973, the Mars-6 spacecraft (expedition M-73) was launched from the left launcher of site No. 81 of the Baikonur Cosmodrome. The goals of this vehicle can be divided into two large blocks of tasks: the goals of the approaching vehicle and the goals of the descent vehicle (DS). The objectives of the approaching vehicle were: studying the composition and density of the atmosphere, studying the relief, determining the brightness temperature of the atmosphere, measuring magnetic field. The objectives of the descent vehicle were: measuring the characteristics of the atmosphere in height, measuring chemical composition atmosphere, study of surface rocks, obtaining the first images from the surface of Mars, determination of the mechanical characteristics of the surface soil layer.

Figure 1. Mars-6 orbiter and descent vehicle [http://zelenyikot.com/mars-6/]

During the part of the expedition intended to deliver the SA to the surface of the planet, the separation scheme and landing on the surface of the planet occurred as follows. The descent vehicle enters the atmosphere at an entry angle of 11.7° at a speed of 5600 m/s. In the section of passive aerodynamic braking, the stability of the aircraft was ensured by its shape and alignment. When the speed reached 600 m/s, the parachute system was put into operation. During parachute descent at altitudes of 20 km, measurements of temperature, pressure, and chemical composition of the atmosphere were carried out. The results were transmitted to the flyby vehicle, but helpful information was isolated only from the SA radio complex. Immediately before landing, contact with the aircraft was lost. The last telemetry received from it confirmed the issuance of a command to turn on the engine soft landing. A reappearance of the signal was expected 143 seconds after the disappearance, but this did not happen.

It was not possible to unambiguously determine the reason for the unsuccessful completion of the SA. The most likely versions include the following:

• the device crashed, including due to the failure of the radio complex at a descent speed of 60 m/s;
• The emergency situation was caused by the amplitude of the apparatus' oscillations being exceeded under the influence of the Martian storm at the moment the soft landing engines were turned on.

Figure 2. Model of the Mars-3 apparatus after a hard landing

Among the results of this mission, one can highlight the fact that for the first time data on the parameters of the Martian atmosphere were transmitted to Earth, measurements of the chemical composition of the atmosphere, pressure, ambient temperature. The results of these measurements were very important both for expanding knowledge about the planet and for identifying the conditions under which future Mars stations should operate.

Currently, a search is underway for the crash site of the Mars-6 spacecraft; for this purpose, specialists and enthusiasts carried out a visual review and analysis of high-resolution images of the expected impact zone, which were taken by the Mars Reconnaissance Orbiter satellite. Several craters were selected as possible impact sites, and therefore, to obtain updated data, it was decided to resort to modern methods of numerical modeling of physical processes.

Geometry and design solutions of the Mars-6 spacecraft

Figure 3 shows a general cross-sectional view of the Mars-3 descent vehicle and a photograph of the vehicle’s mock-up. The model of the Mars-6 apparatus was built on the basis of data about the Mars-3 apparatus, since from the point of view of mass-rigidity characteristics, they are similar.

Figure 3. Design of the Mars-3 satellite

The main parameters of the SA that influence the formation of a crater upon impact are the mass of the SA and its shock-absorbing structural elements. The total mass of the Mars-6 apparatus was 3880 kg, of which the mass of the scientific equipment of the orbital compartment was 114 kg, the mass of the descent vehicle was 1000 kg. The corrective propulsion system was filled with 598 kg of fuel. The mass of the descent vehicle upon entry into the Martian atmosphere is 844 kg. The mass of the automatic Martian station after landing is 355 kg, of which the mass of scientific equipment is 19 kg. It is worth noting that the center of mass of the Mars-6 spacecraft is located in the lower third of the vehicle in order to create a “tumbler” effect and the vehicle always turns over on its bottom after impact with the surface of the planet.

The depreciation of the Mars-6 satellite was carried out under the conditions of landing on the surface of Mars with a vertical speed of up to 10 m/s and a lateral speed of up to 30 m/s; actual overloads should not exceed 180 g; in peripheral locations, overloads should not exceed 240 g. The shock absorption of the lower part of the body, 270 mm thick, consisted of three layers of foam. Externally, the shock absorption of the SA was protected by a layer of fiberglass laminate 1.5 mm thick. The SA was equipped with a protective casing for the station equipment, as well as to protect the petal supports from damage. The protective casing had additional external shock absorption to protect the lander and equipment from repeated impacts from the side surface. The rear casing cushioning consisted of two layers of foam. Also, to strengthen the structure, several stiffening ribs and aluminum tubes were introduced between the shock-absorbing layer and the petals of the automatic station.

When creating a computational model of the descent vehicle to accurately describe the physical processes, the nonlinear properties of materials were taken into account, namely, the elastic-plastic properties of the materials from which the casing is made, internal structural elements and energy absorber - fiberglass composite, aluminum alloy and foam, respectively. To model the nonlinear properties of glass fiber and aluminum alloy, a bilinear elastic-plastic model of the material with kinematic hardening with the possibility of element destruction was used. To model the plastic properties of foam plastic (Figure 4), a model of progressive destruction with the possibility of pore collapse and compaction was used.

Figure 4. PS-1 foam compression diagram

Estimated area of ​​impact of the Mars-6 spacecraft

The landing area for the Mars 6 lander was chosen in the low-lying Eritrean Sea in southern hemisphere Mars. The descent vehicle, according to the processing of trajectory measurements carried out in 1974, landed in an area with nominal coordinates of 23.9° S. w. and 19.5°W The approximate landing site of the Mars-6 spacecraft on the map of Mars is shown in Figure 5.

Figure 5. Mars 6 landing site

As can be seen from the map, the closest successfully landed vehicle to the Mars-6 spacecraft is Opportunity rover. It is also clear from the map that the Opportunity rover and the Mars-6 spacecraft are located on the same plain, so we can assume that the landscape and properties of the regolith in the area where the Mars-6 spacecraft fell are close to the properties of the regolith in the landing area of ​​the Opportunity rover . The soil at the landing site of the Opportunity rover is a layered structure. On the surface there is aeolian sediments that cover the thickness of layered soil.

Description of the properties of aeolian sands

Aeolian sands are a fine structure that is formed during wind erosion. It is a light and free-flowing structure that has a grain size of 0.1-10 microns. Types of different aeolian sands are presented in Figure 6.

Figure 6. Aeolian sands on the surface of Mars

The physical and mechanical properties of aeolian sands are presented in Table 1.

Table 1. Physico-mechanical properties of aeolian sands of Mars

Description of the properties of rocky soil

Rocky soil is the most durable type of regolith, which is formed from a mixture of soil and debris. Aeolian sediments and rocky soil apparently form a cover on the surface of rocks over the entire surface of the plain on which the Opportunity rover and the Mars-6 spacecraft landed. Types of rocky soil are presented in Figure 7.

Figure 7. Rocky soil on the surface of Mars

The physical and mechanical properties of rocky soil are presented in Table 2.

Table 2. Properties of rocky soil on Mars

To simulate the behavior of the soil of Mars, the Mohr-Coulomb model was chosen, which allows us to describe the dependence of the tangential stresses of the material on the magnitude of the normal stresses. This model is based on the hypothesis about the dependence of the ultimate tangential stress on the average normal stress, which is caused by internal friction in the material. When loaded, soils work predominantly in shear along the surface with the lowest bearing capacity. Therefore, shear strength is the determining strength characteristic for soils. Failure occurs at the moment when the magnitude of the shear stress reaches the shear strength limit of the soil. To conduct research, a two-layer soil model was built, where upper layer is a layer of aeolian sediments, and the bottom layer is rocky soil. Since the values ​​of the properties of the soil of Mars are not completely defined, but are specified in a certain range, the work analyzed the dependence of the results on the properties of the soil (“hard soil” and “ soft ground»).

Numerical solution of the problem

To numerically solve the problem, the LS-DYNA software package was chosen as a tool. To simulate the impact process, we used the formulation of the Lagrange-Eulerian interaction based on structured meshes (Structured Arbitary Lagrange Eulerian, S-ALE), which allows us to describe large deformations of the medium without deforming the finite elements, which leads to more stable and correct results. The computational model of the Mars-6 apparatus and the soil area is presented in Figure 8.

Figure 8. Calculation model of the Mars-6 apparatus and soil

The finite element model of the apparatus contains 29,232 nodes, the model of the soil area - 94,500 nodes. In total, about 400 thousand equations are solved at each time step. The time of one calculation (0.3 seconds of the impact process) takes about 4-8 hours on a workstation with a Corei7 processor.

In the process of modeling the fall of the Mars-6 spacecraft, modeling of the normal landing was carried out to confirm the correctness of the choice of the calculation model, as well as modeling of an emergency landing under different angles falls, with different values ​​of physical and mechanical parameters of the soil material. Example of calculation results with initial speed 60 m/s and an angle of attack of 10 degrees is shown in the animation. The process includes contact of the device with the ground, elastic-plastic deformation of the device and the soil in the impact area, rebound of the device and scattering of soil elements.

As a result of multivariate modeling, ranges of crater width values ​​after the fall of the Mars-6 satellite were obtained, which are presented in Figure 9.

Figure 9. Ranges of possible crater diameters after fall of the Mars-6 spacecraft

In front of everyone possible options Given the angles of incidence of the Mars-6 satellite, the acceleration on the equipment exceeds the critical acceleration, which means that the satellite fails in all the presented cases.

As a result of the modeling, it was determined that the width of the crater, depending on the angle of incidence, varies from 3.5 m to 4.2 m when the Mars-6 satellite falls into “hard ground” and from 4.6 m to 5.5 m when falling into “soft ground”. The distance to the repeated contact point (Figure 10) varies from 0 m to 46 m when falling into “soft ground” and from 0 m to 99 m when falling into “hard ground”, depending on the angle of incidence of the Mars-6 satellite.

Figure 10. Ranges of possible crater diameters after fall of the Mars-6 spacecraft

When considering the estimated area of ​​impact of the Mars-6 satellite, determined by Anton Gromov, in a photograph from a satellite image (Figure 11), one can notice that the distance between the craters is approximately 9 m, when the width of the crater itself is approximately 4 m. These values ​​correspond to ranges of the obtained numerical modeling data, therefore we can say that this crater could have remained after the impact of the Mars-6 spacecraft. Further study of this alleged crash site is necessary using high-precision satellite photography.

Figure 11. Estimated crash site of the Mars-6 spacecraft

As a result of the work, the following results were obtained:

• A numerical modeling technique was selected, a model of the Mars-6 satellite was created, and a model of the Martian soil was selected;
• The calculation model was validated by simulating a standard landing;
• The results of modeling the fall of the Mars-6 apparatus in abnormal mode were obtained;
• Based on the results of multivariate modeling, the dimensions of the crater from impacts at different angles for different soil hardness were determined;
• Defined possible distances to the point of secondary contact with the surface.

Literature

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2. Evans Jonson, Walker An Eulerian approach to soil impact analysis for crashworthiness applications [Journal]. - Durban: International Journal of Impact Engineering, 2010
3. Fasanella Jackson, Kellas Soft Soil Impact Testing and Simulation of Aerospace Structures [Journal]. - Hampton: Proceedings of the 10th LS-DYNA Users Conference, 2008
4. Hallquist LS-DYNA Keyword User Manual [Book]. - Livermore: Livermore Software Technology Corporation, 2007.
5. Ozturk U. E. Anlas G. Finite element analysis of expanded polystyrene foam under multiple compressive loading and unloading [Journal]. - Gebze: Materials and Design, 2010
6. Qasim H. Shah A. Topa Modeling Large Deformation and Failure of Expanded Polysterene Crushable Foam Using Ls-Dyna [Journal]. - Kuala Lumpur: International Islamic University Malaysia, 2013
7. Bazhenov Kotov Math modeling non-stationary processes impact and penetration of axisymmetric bodies and identification of properties of soil media [Book]. - Moscow: FIZMATLIT, 2011.
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9. Demidov N.E. Bazilevsky A.T. Soil of Mars: varieties, structure, composition, physical properties, drillability and dangers for landing vehicles [Article] // Astronomical Bulletin. - Moscow: [b.n.], 2015 - 49(4).
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Last spring, Vitaly Egorov, a Russian space enthusiast (at this moment an employee of Russia's first private company Dauria Aerospace), in collaboration with users of the social network Vkontakte, in photographs of the Martian surface, the lost Soviet descent vehicle Mars-3.

Now, Vitaly Egorov invites everyone to start searching for the Soviet research station “Mars-6”, which was also lost. He wrote about this on his blog.

The automatic interplanetary station "Mars-6" was launched into orbit using the Proton-K launch vehicle on August 5, 1973 at 21:45 Moscow time. On March 12, 1974, the Mars 6 lander began to enter the dense layers of the atmosphere. The landing on Mars took place without failures: braking against the atmosphere by a heat shield, opening the parachute, transmitting data to Earth about the orientation, overloads and even the composition of the atmosphere of the Red Planet. However, on last stage landing, communication with the device was interrupted. At the moment its exact location is unknown. Only the intended landing site is known.

“It is within our power to work together to find the lost station and solve a forty-year-old mystery,” writes Egorov.

NASA's Mars Reconnaissance Orbiter will help us in our search, on board which is a high-resolution camera called HiRise, capable of photographing the Martian surface with a detail of 25 centimeters per pixel. Thus, it was thanks to her photographs that the lost Soviet spacecraft Mars-3 was discovered.

Fortunately, MRO was surveying the surface of the planet where the Soviet landing site may be located. According to Egorov, “the surface area covered by these frames is 964.5 square kilometers. There may be a parachute, a brake shield and the Mars-6 descent module itself.” But there is no 100% guarantee that the desired objects were found in these frames. If we look through all the fragments and don’t find anything similar, we will contact NASA with a request that they complete the missing fragments of the entire territory. But even this does not guarantee the success of our searches: if an error crept into the calculations of Soviet ballisticians, or they did not take into account any factors, then Mars-6 flew to where no one thought to look for it. But even this will add information, and Based on this, it will be possible to clarify the circumstances of the landing."

The gray ellipse is the proposed landing site. Numbered rectangles are areas filmed by camera HiRise, which we will review. Illustration: Vitaly Egorov

We note information that may help in finding the device. It is known that the first to fire was the brake shield, which flew further along its trajectory. Unlike Mars 3, Mars 6 did not have a separate parachute, braking engine, and parachute container. Also, in case of a successful landing, the foam casing was shot off, but we do not know whether the landing was successful.

Communication with the device was lost after the probe separated from the parachute and braking engine. Therefore, we can only speculate what happened next. And according to calculations, the separation of the descent vehicle from the parachute system should have occurred at a height of several meters from the surface. This suggests that Mars 6 should be located near the parachute. But there is a possibility that there is an error in the estimates of the distance to the surface.

Landing diagram for Mars 6. Animation: Vitaly Egorov

"...the fastenings could come loose ahead of time and the probe could simply break, falling from high altitude. Or, on the contrary, it did not have time to disengage, the braking motor did not work, and the probe crashed on the surface. In this case, only the shield should lie separately,” adds Vitaly.

And that's not all the difficulties. In 40 years, sandstorms could cover the parachute without leaving a trace. And if this happened, “then we will not be able to identify the landing module, even if we find it. It is encouraging that with Mars 3 the error in calculating the landing site was only 3 kilometers, which is an impressive result for 1971. And the Mars 3 parachute is still visible even today, which is also in our favor."

However, there is also positive points touching the surface of the planet. In the case of Mars 3, the surface was strewn with many boulders, which complicated the search, since Martian rock could be confused with the vehicle. In the case of Mars 6, the surface is bare plains filled with sand dunes.

And so, let's move on to the search itself. Vitaly, as a warm-up, posted links to fragments of images obtained by the MRO probe, which can be downloaded and carefully viewed. How the work is planned, Egorov wrote the following: “I recommend that you first write in the comments who has downloaded and viewed which fragment. It is advisable to post findings in the same thread. If you come across something suspicious or interesting, take a screenshot and post the picture in the comments. In the signature indicate the fragment number (or leave it in the thread where it is already discussed), and the exact location of the found object. Do not insert images larger than 700 pixels in width. It is advisable for several people to view each fragment, since one person may miss something.

“We searched for Mars-3 through VKontakte, but in LiveJournal (where the searches take place) authorization from different social networks is possible, which allows us to significantly expand the audience of searches.”

Frame 1

Pixel size 53 cm.

The lander will be only 3 pixels in size (it’s almost useless to search),

Start space age passed under the sign of Mars. Scientists believed that natural conditions on the Red Planet differ little from those on Earth, so the neighboring world is ideal for colonization. Even if there isn't intelligent beings, then there must certainly be some kind of flora and at least primitive fauna. The so-called “canals” also attracted attention - thin straight lines on the red surface, which some astronomers mistook for irrigation structures of the Martians, others - for forests along ancient drying up reservoirs.

Mars was seen as main goal expansion, the founders of space rocketry Wernher von Braun and Sergei Korolev: the projects they were working on included sending huge interplanetary ships, and the planned expeditions were supposed to take years.

However, before that it was necessary to make sure that Mars really has dense atmosphere and water resources.

The first automatic station, listed in secret documents under the designation 1M, was planned to be sent by Soviet specialists in September 1960, when an “astronomical window” opened for launches to the Red Planet. For this station, Professor Alexander Ignatievich Lebedinsky prepared a massive block of equipment, which included a phototelevision device and a spectroreflexometer designed to determine whether there is life on Mars. Chief designer Sergei Pavlovich Korolev suggested preliminary testing of the block in the steppe, near the cosmodrome. The device showed that there is no life in Kazakhstan, which caused numerous jokes from rocket scientists. As a result, the Lebedinsky block remained on Earth.

Due to delays in preparing the rocket, the launch was postponed several times.

After all, when the hope is that the station will pass there was no longer any space left near the Red Planet, the launch took place.

On October 10, 1960, the Molniya launch vehicle with the 1M No. 1 apparatus went into the sky and immediately crashed. Experts feverishly prepared a second launch, but it also ended in vain.

The next “astronomical window” opened in 1962. This time, scientists were going to send three WW2 series stations into space. Two of them entered low-Earth orbit on October 24 and November 4, but repeated the fate of their predecessors. Only one launch was successful: on November 1, the upper stage transferred the automatic station 2MV-4 No. 2, now known as Mars-1, to an interplanetary trajectory. I managed to keep in touch with her for almost five months. During this time, the station approached Mars at a distance of 195,000 km, but on March 21, 1963, due to problems with on-board equipment, it fell silent.

Things didn’t go very well for the Americans at first either. The first interplanetary station launched to Mars on November 5, 1964 was Mariner 3 (Mariner-3, Mariner-C), and even early in its flight it went out of control. Three weeks later, on November 28, Mariner 4 (“Mariner-4”, “Mariner-D”) was launched, and now fortune smiled on the Americans. The station flew 10,000 km from Mars, took twenty-two photographs on July 14, 1965, and transmitted them to Earth the next day. They showed a surface densely pitted with craters and completely lifeless. No canals, signs of forests or water flows were found on the planet.

NASA Model of the Mars-1 apparatus

It turned out that Mars was more like the Moon than the Earth.

Disappointment with the Red Planet has led to disappointment in astronautics in general. Conversations began that studying " dead worlds“Nobody needs that it only brings losses. At the same time, voices were heard criticizing the reliability of the images transmitted by the station. Supporters of continued research (among them were the famous scientists Clark Chapman, James Pollack and) pointed out that Mariner 4 photographed only a small part of the surface, from which it is impossible to judge the planet as a whole.

One way or another, the research continued. It was necessary to draw up new maps of Mars, clearing them of errors that had accumulated over a century of observations. February 24 and March 27, 1969 NASA employees launched two more automatic stations to Mars: Mariner-6 (“Mariner-6”, “Mariner-F”) and “Mariner-7” (“Mariner-7”, “Mariner-G”). The first flew 3,390 km from Mars and took 76 pictures; the second approached to a distance of 3,500 km and sent 126 images to Earth. Up to 10% of the Martian surface was photographed. The data from the previous mission were fully confirmed: an inhospitable and very monotonous world opened up before the scientists.

Smooth landing

Still, it was not easy to abandon the exciting idea of ​​Martian life. There were optimists in the scientific community who believed that the climate on the Red Planet was once milder than today, and simple microorganisms could have developed on it. Their search was to be carried out by special robotic complexes delivered to the surface of the planet.

Soviet scientists were again the first to attempt to land on Mars.

The M-71 project was approved, providing for the sending of three automatic stations in 1971. The M-71C station was supposed to launch earlier than the others and enter the orbit of the artificial satellite of Mars; the other two would deliver landers to the surface of the planet, and their orbital modules would conduct remote research. When landing on Mars, the apparatus, equipped with a variety of measuring equipment, had to, following commands from the onboard automation, separate the protective casing, open the “petals” of the housing and assume a vertical position. After this, transmitters and scientific equipment were turned on; An X-ray spectrometer and a cross-country ability assessment device, PrOP-M (the first Mars rover!), were brought to the ground, which made a short journey, studying the physical properties along the way. Within 25 minutes, the panorama and scientific information would be broadcast to the orbital module for relay to Earth.

It is interesting that the designers took into account the possibility of “infection” of Mars with terrestrial microorganisms and tried to reduce it to a minimum: individual parts of the descent module were carefully sterilized, and its assembly was carried out in a special “clean” block with an airlock chamber, filters and bactericidal lamps.

The M-71S station, designated “Cosmos-419” at launch, launched on May 5, 1971, but remained in low-Earth orbit. On May 19 and 21, 1971, the Mars-2 (M-71 No. 171) and Mars-3 (M-71 No. 172) stations were launched onto the interplanetary trajectory. This time, the Proton-K rockets and upper stages “worked” flawlessly. Three stations - two Soviet M-71 and one American Mariner-9 (Mariner-9, Mariner-I), launched on May 30 - silently flew to the neighboring planet. However, in September a sand and dust storm began on Mars, and the Soviet stations, working according to a pre-established program, could not wait out it. On November 21, the Mars 2 lander entered the atmosphere under too much high angle and crashed on the surface of the planet. The Mars 3 lander attempted to reach the surface on December 2. It entered the atmosphere at a speed of 5800 m/s, reduced its speed due to aerodynamic braking, opened its parachute and made a soft landing. During descent, the device transmitted blind frames for 15 seconds, after which communication with it was lost.

Meanwhile the storm continued to rage. Orbital modules carried out surveys, but dust completely hid the relief.

The research program was hopelessly disrupted.

Only in last days By 1971, the atmosphere began to clear, and on January 2, 1972, Mariner 9 began mapping. Unlike its Soviet counterparts, its computer could be reprogrammed, making this orbital station the only one launched in May 1971 that was able to complete its mission.

The last "Mars"

Soviet rocket scientists decided to take revenge two years later. In July and August 1973, they launched four M-73 series stations to Mars at once. It seemed that this time luck would smile on Soviet scientists. All four launch vehicles worked as they should, and a string of vehicles flew towards the neighboring planet: orbital Mars-4 (M-73 No. 52C), orbital Mars-5 (M-73 No. 53C), landing Mars-5 6" (M-73 No. 50P) and landing "Mars-7" (M-73 No. 51P).

Unfortunately, none of these stations was able to fully implement the research program. On February 10, 1974, due to a malfunction in the on-board computer, the braking propulsion system of Mars-4 did not turn on, and the station missed the target at a distance of 2200 km, transmitting only one image to Earth. On February 12, Mars 5 entered an areocentric orbit, but quickly wasted energy and managed to photograph only a small part of the planet’s southern hemisphere. On March 9, the descent module of the Mars-7 station missed the Red Planet, passing 1,300 km from its surface. On March 12, the Mars-6 station's descent module entered the Martian atmosphere, released a parachute and began transmitting the first data. However, after 150 seconds the connection with him was lost.

The domestic Mars exploration program suffered a severe blow.

Despite many years of discussion of various initiatives, including a project to deliver samples of Martian soil to Earth, no other serious attempts were made to land on the neighboring planet - Soviet scientists focused on Venus.

Space archaeologists

Until recently, little was known about the fate of Mars 3 and Mars 6, which made a soft landing on the Red Planet. However, the appearance space stations a new generation, capable of seeing even small objects from orbit, has opened up fantastic opportunities for space archaeologists.

The first success came to Vitaly U, known on the Internet under the pseudonym Green Cat and now actively promoting astronautics.

In November 2012, he drew attention to the fact that no one is even trying to find many “historical” vehicles that landed on Mars, although the Mars Reconnaissance Orbiter (MRO) with a high-resolution camera HiRISE orbits the Red Planet (High Resolution Imaging Science Experiment).

After analyzing photographs of the Ptolemy crater, Egorov found suitable objects and turned to specialized specialists with a request to confirm its discovery. NASA responded and adjusted the MRO's work to provide a more detailed survey of the area. In April 2013, the Mars 3 lander was found.

NASA

A year later, a group of enthusiasts began searching for Mars 6, which landed in the low-lying part of the Erythraean Sea in the southern hemisphere of Mars. The problem turned out to be more difficult, and its solution took much longer: only two weeks ago Vitaly Egorov finally announced that he had managed to identify the crater formed when the descent module fell to the surface. Of course, the discovery requires confirmation, but it seems that Mars has become one less mystery.

Unfortunately, the Russian program for studying the bodies of the Solar System is developing very sluggishly. In the coming years, domestic specialists are preparing to reproduce the experience of lunar launches carried out by the team more than half a century ago. One should hardly count on a quick Martian breakthrough.

MOSCOW, July 20 – RIA Novosti. A group of Russian enthusiasts, using images from the American Mars Reconnaissance Orbiter (MRO) satellite, found the probable location where the descent module of the Soviet interplanetary station Mars-6 crashed on Mars in 1973. This was reported to RIA Novosti by the initiator of the search, popularizer of astronautics Vitaly Egorov and the author of the discovery Anton Gromov.

In 2013, Egorov, thanks to the study of photographs, found the descent module of the Mars-3 station.

“Interplanetary spacecraft for humanity are like sense organs that we send to other worlds. I have been inspired by this idea since childhood, and at the end of the article about the successful search for Mars-3 it was said that Mars-6 has not yet been found. Of course, I immediately wanted to give humanity knowledge about its fate,” said the author of the discovery, Anton Gromov.

The initiator of the search, Egorov, told RIA Novosti that a group of enthusiasts looked at high-resolution satellite images of the alleged fall zone.

“Gromov discovered a crater that could have remained after the fall of Mars-6. To obtain updated data, it was decided to resort to modern methods of numerical modeling of physical processes. An engineering company from St. Petersburg, at the request of enthusiasts, conducted a “virtual crash test” of the descent module.” Mars-6" to find out the picture of the incident. The obtained values ​​correspond to the visible data, so we can say that a specific crater could have been left after the impact of the Mars-6 descent module," said Egorov.

According to the simulation results, Mars-6 should have left a crater with a diameter of about four meters when falling into hard ground and about five meters in diameter when falling into soft ground. It could rebound upon impact with the surface at a distance of 46-99 meters, depending on the type of surface of the planet. It was just such a crater that enthusiasts found in the low-lying part of the Erythraean Sea in the southern hemisphere of the Red Planet, where the lander supposedly fell.

The authors of the discovery note that to verify the accuracy of the calculations, further study of the alleged crash site is required using high-precision satellite photography. To do this, they intend to wait for new images from MRO, which NASA will post after the global dust storm ends on Mars.

Mars-6 is a Soviet interplanetary station, which was launched in 1973 from the Baikonur Cosmodrome on a Proton-K rocket. It consisted of a flight block and a landing module - a descent module. The flight unit studied the composition and density of the atmosphere, the topography of Mars, determined the brightness temperature of the atmosphere and measured the magnetic field. The purpose of the launch is to measure the altitude characteristics of the atmosphere, the chemical composition of the atmosphere, study surface rocks, obtain the first images from the surface of Mars and determine the mechanical characteristics of the surface soil layer.

The orbital station remained in the asteroid belt, and the descent vehicle deployed a parachute and managed to analyze the composition of the atmosphere, but at the moment the braking engines were turned on, communication with it was interrupted. The exact cause of the accident is unknown. For the first time in history, this Soviet station transmitted data on the chemical composition, pressure and temperature of the Martian atmosphere.

"Mars-6" (M-73P No. 50)- Soviet automatic interplanetary station (AMS) of the M-73 series under the Mars program, launched on August 5, 1973 at 17:45:48 UTC. The M-73 series consisted of four fourth-generation spacecraft designed to study the planet Mars. The Mars-4 and Mars-5 spacecraft (modification M-73S) were supposed to enter orbit around the planet and provide communication with automatic Martian stations designed to operate on the surface. Descent vehicles with automatic Martian stations were delivered by the Mars-6 and Mars-7 spacecraft (modification M-73P).

The descent vehicle of the AMS Mars-6, in contrast to the descent vehicle of the AMS Mars-7, identical in design, landed on the planet.

Specifications[ | ]

Orbiter[ | ]

Main structural element, to which the units are attached, including the propulsion system, solar panels, parabolic highly directional and low-beam antennas, radiators of the cold and hot circuits of the thermal management system and the instrumentation, serves as a block of fuel tanks of the propulsion system.

Important difference modifications M-73S and M-73P is to place scientific equipment on an orbital vehicle: in the satellite version, scientific equipment is installed in the upper part of the tank block, in the version with a descent module - on a conical transition element connecting the instrument compartment and the tank block.

For the 1973 expedition vehicles, the KTDU was modified. Instead of the main engine 11D425.000, an 11D425A is installed, the thrust of which in low thrust mode is 1105 kgf (specific impulse - 293 seconds), and in high thrust mode - 1926 kgf (specific impulse - 315 seconds). The tank block was replaced with a new one - large in size and volume due to the cylindrical insert, while larger consumable fuel tanks were also used. Additional helium cylinders were installed to pressurize the fuel tanks. Otherwise, the orbital vehicles of the M-73 series, in terms of layout and composition of on-board equipment, with a few exceptions, repeated the M-71 series.

Descent vehicle[ | ]

On orbital vehicles M-73P, the descent module is attached to the upper part of the propulsion system fuel tank block using a cylindrical adapter and a connecting frame.

The lander includes:

The descent module was equipped with equipment for measuring the temperature and pressure of the atmosphere, mass spectrometric determination of the chemical composition of the atmosphere, measuring wind speed, determining the chemical composition and physical and mechanical properties of the surface layer, as well as for obtaining a panorama using television cameras.

Weight [ | ]

The total mass of the Mars-6 spacecraft was 3880 kg, of which the mass of the scientific equipment of the orbital compartment was 114 kg, the mass of the descent vehicle was 1000 kg. The corrective propulsion system is filled with 598.5 kg of fuel: 210.4 kg of fuel and 388.1 kg of oxidizer. The mass of the descent vehicle upon entry into the Martian atmosphere is 844 kg. The mass of the automatic Martian station after landing is 355 kg, of which the mass of scientific equipment is 19.1 kg.

Technological novelty of the project[ | ]

For the first time in practice domestic cosmonautics Four unmanned spacecraft simultaneously participated in one interplanetary expedition. In preparation for the expedition, the modernization of ground-based experimental and testing bases and the ground-based command and measurement complex, which began for the M-71 series vehicles, continued.

Thus, to check and clarify thermal calculations, special vacuum installations equipped with simulators have been created solar radiation. An analogue of automatic spacecraft underwent a full range of complex thermal vacuum tests, the task of which was to test the ability of the thermal control system to maintain the temperature regime within specified limits at all stages of operation.

Mission objectives and goals[ | ]

Descent vehicle.

Fly-by vehicle[ | ]

Lander[ | ]

Project implementation[ | ]

All M-73 series spacecraft have successfully completed the entire cycle of ground tests. Launches of these automatic spacecraft in accordance with Soviet program research outer space and planets of the solar system were carried out in July - August 1973.

Flight [ | ]

Flight diagram.

During the flight of the M-73P spacecraft (“Mars-6 and 7”), intended to deliver the descent vehicle, the scheme of separation and landing of the spacecraft is completely repeated. Martian surface, which was developed for the previous M-71 expedition. The most important stage of the expedition - landing on the Martian surface - is carried out as follows. The descent vehicle enters the atmosphere within a given range of entry angles, at a speed of about 6 km/s. In the passive aerodynamic braking section, the stability of the descent vehicle is ensured by its external shape and alignment.

The orbital (flyby) vehicle after the separation of the spacecraft and during its subsequent approach to Mars - this is the difference from the M-71 flight pattern - is deployed using a gyroplatform in such a way that the meter-range antennas are rotated to receive a signal from the descent vehicle, and the highly directional antenna is turned to transmitting information to Earth. After completing work with automatic Martian station The device continues to fly in a heliocentric orbit.

Flight Control[ | ]

To work with the M-73 series spacecraft, the Pluto ground radio complex, located at NIP-16 near Evpatoria, was used. When receiving information from spacecraft to long distances To increase the potential of the radio link, summation of signals from two ADU 1000 antennas (K2 and K3) and one KTNA-200 antenna (K-6) was used. Commands are issued through antennas ADU 1000 (K1) and P 400P (K8) at the second site of NIP-16. Both antennas are equipped with Harpun-4 UHF transmitters capable of emitting power up to 200 kW.

From the point of view of session control of the spacecraft, some changes have been made to the logic of the functioning of on-board systems: for the M-73P vehicles, the standard session 6T, intended for braking and entering the orbit of the Mars satellite, has been excluded.

Flight program execution[ | ]

The Mars-6 spacecraft (M-73P No. 50) was launched from the left launch pad of site No. 81 of the Baikonur Cosmodrome on August 5, 1973 at 20:45:48 by the Proton-K launch vehicle. With the help of three stages of the Proton-K launch vehicle and the first activation of the remote control accelerating block The spacecraft was launched to an intermediate satellite satellite with an altitude of 174.9-162.9 km. The second switching on of the upper stage propulsion system after ~1 hour and 20 minutes of passive flight resulted in the spacecraft transitioning to the flight path to Mars. At 22:04:09.6 the spacecraft separated from the upper stage. On August 13, 1973, the first correction of the movement trajectory was performed. When setting the settings, the readiness of the first channel of the onboard computer of the ACS was removed, but during the correction session it was restored. The correction impulse was 5.17 m/s, the engine operating time at low thrust was 3.4 seconds, fuel consumption was 11.2 kg. Almost immediately the first set of on-board tape recorder EA-035 failed. The situation was corrected by switching to the second set. However, just a month after the launch, on September 3, 1973, the telemetry on the device failed, as a result of which it became impossible to receive information in direct transmission mode via the decimeter channel, and via the centimeter channel it was possible to transmit information only in playback mode, and only information from the FTU and a VCR. We had to change the control technology and issue all commands two or three times “blindly” during the entire flight, monitoring their passage only by indirect signs.

15 minutes after separation, the SA braking engine fired, and 3.5 hours later, the descent vehicle entered the Martian atmosphere at 09:05:53 at a speed of 5600 m/s (20160 km/h). The entry angle was −11.7°. At first, braking was carried out due to the aerodynamic screen, and after 2.5 minutes, when the speed reached 600 m/s (2160 km/h), the parachute system was put into operation. During the parachute descent stage, at altitudes from 20 km to the surface and below, temperature and pressure measurements were taken, and the chemical composition of the atmosphere was determined. Within 149.22 seconds, the results were transmitted to the flight vehicle, but useful information was extracted only from the signal from the SA radio complex. The signal from CD 1, turned on 25 minutes before entry into the atmosphere, was very weak, so the information from it could not be deciphered.

The entire descent section - from re-entry and aerodynamic braking to parachute descent inclusive - lasted 5.2 minutes. Total time descent by parachute, starting from the moment the signal was given to insert the parachute system, was 151.6 seconds. During the descent there was no digital information from the MX 6408M device, but with the help of the Zubr, IT and ID devices, information about overloads, changes in temperature and pressure was obtained. Immediately before landing, communication with the aircraft was lost. The last telemetry received from it confirmed the issuance of a command to turn on the soft landing engine. A reappearance of the signal was expected 143 seconds after the disappearance, but this did not happen.

The landing area for the Mars 6 lander was chosen in the low-lying Erythraean Sea in the southern hemisphere of Mars. Aiming point coordinates 25° S. latitude, 25°w. d. The descent vehicle, according to the processing of trajectory measurements carried out in 1974, landed in an area with nominal coordinates of 23.9° S. w. and 19.5° W. d. (According to another processing of trajectory measurements carried out in 1974 in the Margaritifer Terra area with nominal coordinates 23.54° S, 19.25° W.) The landing occurred in the calculated area of ​​coordinate scatter.

It was not possible to clearly determine the reason for the unsuccessful completion of work with the SA. The most likely versions include:

results [ | ]

The flight program of the Mars-6 spacecraft has been partially completed. The lander program ended in failure.

Scientific results

The Mars-6 lander landed on the planet, transmitting to Earth for the first time data on the parameters of the Martian atmosphere obtained during its descent.

The Mars 6 lander measured the chemical composition of the Martian atmosphere using a radio frequency mass spectrometer. Soon after the main parachute deployed, the analyzer opening mechanism was activated, and the atmosphere of Mars gained access to the device. The mass spectra themselves were supposed to be transmitted after landing and were not obtained on Earth, however, when analyzing the current parameter of the magnetic ionization pump of the mass spectrograph, transmitted via a telemetry channel during the parachute descent, it was assumed that the argon content in the planet’s atmosphere could be from 25% up to 45%.

Measurements of pressure and ambient temperature were also carried out on the descent module; the results of these measurements are very important both for expanding knowledge about the planet and for identifying the conditions under which future Mars stations should operate.

Together with French scientists, a radio astronomy experiment was also carried out - measuring radio emission from the Sun in the meter range. Receiving radiation simultaneously on Earth and on board a spacecraft hundreds of millions of kilometers away from our planet makes it possible to reconstruct a three-dimensional picture of the process of generating radio waves and obtain data on the fluxes of charged particles responsible for these processes. This experiment also solved another problem - the search for short-term bursts of radio emission, which can, as expected, arise in deep space due to explosive phenomena in the nuclei of galaxies, during supernova explosions and other processes.

Finding the crash site[ | ]

In 2014, astronautics enthusiasts led by famous blogger and popularizer space research Vitaly Egorov carried out a visual review and analysis of high-resolution images of the proposed landing zone of the descent module, which were taken by the Mars Reconnaissance Orbiter (MRO) satellite.

In 2018, Russian researchers found the likely location where the lander crashed. Modeling showed that Mars 6 would have left a crater with a diameter of about four meters when falling on hard ground and about five meters in diameter when falling in soft ground; the station could also bounce up to 99 meters upon impact. Researchers found just such a crater in a low-lying part of the planet’s southern hemisphere.