The first successful Soviet Martian mission was the dispatch to the "red planet" of the third generation automatic interplanetary station Mars-2. Mars-2 was intended to explore Mars both from its orbit and directly from the surface of the planet.
Mars-2
The AMS consisted of an orbital station (an artificial satellite for the exploration of Mars) and a descent vehicle. Navigation in Space was carried out using orientation to the Sun, the Canopus star and the Earth. The Soviet Union planned to carry out serious research work on Mars, for this the AMS had all the necessary equipment: an infrared photometer for studying the surface relief by measuring the amount of carbon dioxide, an ultraviolet photometer for determining the density of the upper atmosphere. Cosmic ray particle counter and many other devices. The descent vehicle was also automated and configured for autonomous operation and control.
The station was launched from the Baikonur cosmodrome on May 19, 1971. The flight of the station to Mars lasted more than 6 months. The flight was carried out according to the program and, as they say, nothing foreshadowed trouble, only at the last stage (the most important, it should be admitted), due to incorrect calculations, the descent vehicle entered the atmosphere at an angle greater than the specified one, the parachute system was ineffective in such conditions and after passing through the atmosphere of Mars, the device crashed. To the credit of our country, our lander, although it crashed, nevertheless became the first artificial object on the planet. For more than eight months, the orbital station carried out comprehensive studies of Mars, having completed 362 revolutions around the planet during its operation.
Mars-3
The next Russian Mars mission was more successful. When developing the Mars-3 program, the shortcomings of the previous launch were taken into account. Launched 9 days after Mars-2, the Mars-3 station successfully reached Martian orbit six months later. The lander for the first time in history made a soft landing on the surface of the "red planet".
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After one and a half minutes of the preparatory period, the device started to work and began to broadcast a panorama of the surrounding surface, but after 14 and a half seconds, the "Martian show" ended. This “show”, of course, can be called with a big stretch: AMC transmitted only the first 79 lines of the photo-television signal, which was a gray background without a single detail, the same happened with the broadcast from the second telephotometer. Various versions of the incorrect operation of the devices were assumed: corona discharge in the transmitter antennas, damage to the battery … but the final decision on the reasons for the failure was not made. Not otherwise, the Martians have made something clever.
Mars-4
On July 21, 1973, the Mars-4 AMS was launched from the Baikonur cosmodrome. 204 days after the launch, on February 10, 1974, the spacecraft flew at a distance of 1844 km from the surface of Mars. 27 minutes before this moment, one-line optical-mechanical scanners - telephotometers were switched on, with the help of which panoramas of two regions of the surface of Mars were taken (in the orange and red-infrared ranges).
For the first time in the practice of Russian cosmonautics, four spacecraft took part in flight. Many tasks were assigned to Mars-4: studying the distribution of water vapor over the planet's disk, determining the gas composition and density of the atmosphere, measuring the fluxes of electrons and protons along the flight path and near the planet, studying the spectra of the intrinsic glow of the Mars atmosphere, and many others. The main task of Mars-4 was to get in touch with automatic stations on the surface of Mars. The Mars-4 spacecraft carried out photographs of Mars from the flyby trajectory. In the photographs of the planet's surface, which are of very high quality, details up to 100 m in size can be distinguished. This makes photography one of the main means of studying the planet. With its help, using color filters by synthesizing negatives, color images of a number of areas of the surface of Mars were obtained. Color images are also of high quality and are suitable for areological-morphological and photometric studies. Unfortunately, Mars-4 did not fulfill all the tasks assigned to it.
Mars-5
The Mars-5 AMS was launched four days after the Mars-4 launch. The tasks that were assigned to him did not differ much from the previous mission. The Mars-5 station successfully entered orbit around the planet, but the instrument compartment was immediately depressurized, as a result of which the station's operation lasted only about two weeks. The scientific instruments located at the Mars-5 station were mainly intended for studying a number of the most important characteristics of the planet's surface and near-planetary space from orbit. The device was equipped with a Lyman-alpha photometer, designed jointly by Soviet and French scientists, and designed to search for hydrogen in the upper atmosphere of Mars. A magnetometer installed on board measured the planet's magnetic field.
An infrared radiometer operating in the range of 8-40 microns was intended to measure the surface temperature. Artificial satellite of Mars SC "Mars-5" transmitted to the Earth new information about the planet and the surrounding space; high-quality photographs of the Martian surface, including color ones, were obtained from the satellite orbit. Studies of the magnetic field in the near-Martian space carried out by the spacecraft confirmed the conclusion drawn on the basis of similar studies of the Mars-2, -3 spacecraft that there is a magnetic field of the order of 30 gammas near the planet (7-10 times greater than the interplanetary unperturbed fields carried by the solar wind). It was assumed that this magnetic field belongs to the planet itself, and "Mars-5" helped to obtain additional arguments in favor of this hypothesis. For the first time, the temperature of atomic hydrogen in the upper atmosphere of Mars has been directly measured using similar measurements from the Mars-5 spacecraft. Preliminary processing of the data showed that this temperature is close to 350 ° K. Despite the fact that the work of the station did not last long, during its operation, numerous information was obtained about Mars, its atmosphere and magnetic field.
Mars 6
Another of our lander ended up on Mars thanks to the Mars-6 AMS launched from the Baikonur cosmodrome on August 5, 1973. Sadly, this time there was no soft landing either. 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, temperature and pressure changes 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. The reappearance of the signal was expected 143 seconds after the disappearance, but this did not happen, however, the data obtained during the descent has already brought significant results and made a great contribution to the study of Mars. 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 the descent. Mars 6 measured the chemical composition of the Martian atmosphere using an RF-type mass spectrometer. Soon after the opening of the main parachute, the analyzer opening mechanism worked, and the atmosphere of Mars gained access to the device. A preliminary analysis suggests that the argon content in the planet's atmosphere may be about one third. This result is of fundamental importance for understanding the evolution of the atmosphere of Mars. The descent vehicle was also used to measure pressure and ambient temperature; the results of these measurements are very important both for expanding knowledge about the planet and for identifying the conditions in which future Martian stations should operate.
Together with French scientists, a radio astronomy experiment was also carried out - measurements of the solar radio emission in the meter range. Reception of radiation simultaneously on the Earth and on board a spacecraft located hundreds of millions of kilometers away from our planet makes it possible to reconstruct the volumetric picture of the radio wave generation process and obtain data on the fluxes of charged particles responsible for these processes. In this experiment, another problem was also solved - the search for short-term bursts of radio emission, which can, as it is assumed, arise in distant space due to explosive phenomena in the nuclei of galaxies, during supernova explosions and other processes.
Mars-7
Mars 7 was launched on August 9, 1973. This mission to Mars was unsuccessful. The descent vehicle passed 1400 kilometers from the surface of Mars and went into space. Thus, the target program of Mars-7 was not fulfilled, but, making an autonomous flight, the descent vehicle retained its operability and transmitted information to the flight vehicle via radio links KD-1 and RT-1. Communication with the Mars-7 flight vehicle was maintained until March 25, 1974.
During the operation of Mars-7 in September-November 1973, a connection was recorded between the increase in the flux of protons and the speed of the solar wind. Preliminary processing of the Mars-7 spacecraft data on the radiation intensity in the Lyman-alpha resonance line of atomic hydrogen made it possible to estimate the profile of this line in interplanetary space and to determine two components in it, each of which makes an approximately equal contribution to the total radiation intensity. The information obtained will make it possible to calculate the speed, temperature and density of interstellar hydrogen flowing into the solar system, as well as to highlight the contribution of galactic radiation to the Lyman-alpha lines. This experiment was carried out in collaboration with French scientists.
Phobos Project
The Phobos project was the next step in the study of Mars and its satellite. It was launched in the wake of successful cooperation with Western scientific organizations within the framework of the AMS "Vega" project. Despite the fact that the main task of the project remained unfulfilled, and the delivery of descent vehicles to the Mars satellite was planned, the project brought results. Explorations of Mars, Phobos and near-Martian space, carried out for 57 days at the stage of orbital motion around Mars, made it possible to obtain unique scientific results on the thermal characteristics of Phobos, the plasma environment of Mars, and its interaction with the solar wind.
For example, the rate of erosion of the Martian atmosphere caused by interaction with the solar wind was estimated using the ion spectrometer installed onboard the Phobos-2 spacecraft based on the flux of oxygen ions leaving the Martian atmosphere, and the Soviet Mars exploration program ended. The launch of the next, already Russian, apparatus for exploring Mars - the Mars-96 station in 1996 - ended in failure. The launch of the next Russian apparatus for the study of Mars and its satellites (Phobos-soil) took place on November 9, 2011. The main purpose of this device is to deliver a sample of Phobos soil to Earth. On that day, the device entered the reference orbit, but for some reason the command to turn on the propulsion system did not pass. On November 24, attempts to restore working capacity were officially terminated,and in February 2012, the device uncontrollably entered the dense layers of the atmosphere, and fell into the ocean.