CCCP - Venera-13 Mission medal.
Oct. 31, 2021
40 years ago, on October 30, 1981, the Soviet automatic interplanetary station Venera-13 was launched from the Baikonur cosmodrome with the help of the Proton-K launch vehicle and the DM upper stage under the Venus planet exploration program.
For missions of spacecraft of the 4V1 and 4V1M series, the flight-landing scheme was chosen. The differences lie in the duration of the flight (for vehicles of the 4V1M series it is just over 120 days) and the sequence of operations performed by the onboard PA equipment after landing. The operation of the soil intake device begins in the same way as in the previous expedition, 32 seconds after reaching contact with the surface, and the operation of telephotometers - with a 4-minute delay. The first four minutes are devoted to broadcasting information from other scientific instruments and telemetry about the operation of the GZU, and then a panorama of the Venusian surface is transmitted, which continues until radio communication is terminated.
Despite the fact that the devices of the 4V1M series largely repeated their predecessors (Venera-11, -12 of the 4V1 series), 18 experimental machines were manufactured to test all the changes. 39 types of tests are planned to check the operation of resetting telephotometer covers alone. In reality, 78 were carried out. Before shooting, the descent vehicle was heated up to 450 degrees, and then dropped from a height, thereby simulating a landing on the surface of Venus. And only after that the cover was shot off. The tests were carried out on the verge of failure. As a result, with a design margin of operability of new nodes of ~ 7.5, a margin of 20.5 was obtained. With this margin, it was already possible to go on a flight.
The expedition program included:
- Delivery of the descent vehicle to the near-planetary region and provision of the required ballistic conditions for penetration into the atmosphere of Venus;
- Reportage transmission in the process of descent in the atmosphere, containing the results of measurements of its main physical and chemical parameters (pressure, temperature, chemical composition of the atmosphere, moisture content in it), the results of studies of the cloud layer, atmospheric lightning electric discharges;
- Landing on the surface of the planet, on its daytime side;
- Transmission of color telephotometric images of the surface at the landing site and the results of direct soil analysis;
- Retransmission of the results of the scientific program;
- Conducting research of the near-planetary and interplanetary space while moving along the flyby trajectory.
The Venera-13, -14 spacecraft program has been successfully and fully implemented. The lander made a soft landing on the planet's surface in the designated areas. The orbiters, placed on the flyby trajectory, provided reception and retransmission to Earth of information received by each from his lander, including within 127 minutes from the landing site of Venera-13 and more than 56 minutes from the landing site of Venera-14 ".
The main research experiments were carried out within the framework of the planned scientific program of the expedition. The feasibility of interplanetary flight on spacecraft of the Venera series for the purpose of sequential study of two space objects, Venus and Halley's comet, has been confirmed.
For many of these experiments, the word "first time" is applicable. For the first time, color panoramas of the surface of Venus with a circular view were obtained. Moreover, when comparing a number of panoramas obtained during the entire transmission session, dynamic phenomena were found: blowing off the soil layer that fell on the landing platform, changing color shades and fluctuating average illumination. The latter phenomena have not yet been explained.
For the first time, direct measurements have shown that sulfur is the main element that determines the composition of the cloud layer. For the first time, with the help of a soil sampling device, samples of the soil of Venus were taken to determine the elemental composition of rocks by the method of X-ray fluorescence analysis, which required the solution of an extremely difficult problem - namely, the collection of soil samples under conditions of high temperatures and pressures.
During the flight of the descent vehicle in the atmosphere of Venus and after landing on its surface, comprehensive scientific research was carried out. Experiments were carried out to study the chemical and isotopic composition of the atmosphere and clouds, the structure of the cloud layer, scattered solar radiation, as well as the registration of electrical discharges in the atmosphere.
The descent vehicles Venera-13 and Venera-14 carried out experiments in various geological regions of the planet. The landing site was chosen in such a way as to determine the nature of the relief and rocks in one of the most typical geological and morphological provinces of the planet - a hilly upland.
Another important scientific experiment carried out by Venus-13 was the transmission of color panoramic images of the surface. Analyzing the images obtained with its help, scientists hypothesized that they were able to observe the ancient crust of the planet, since the surface in this area is highly eroded (with the exception of bedrock protrusions) and is largely covered with crushed fine-grained material.
The study of individual fragments of panoramas provides additional interesting information. So, in the images transmitted by Venus-13, the release of soil onto the landing platform is clearly visible. Several sequential images of the platform show that the fill soil does not remain stationary, but moves under the influence of the wind. Careful analysis of television images made it possible to clarify the direction and magnitude of the wind speed, determined from acoustic measurements. At the surface of the planet, it was 0.3–0.6 m / s.
Information about the content of water vapor in the planet's atmosphere, collected by previous devices, was contradictory. The "Venera-13" and "Venera-14", equipped for this purpose with a special moisture analyzer, the sensitive element of which was a sensor based on lithium chloride, should have clarified.
The results of measurements indicate a strong dehydration of the atmosphere of Venus, and a peculiar change in vapor concentration depending on altitude indicates that water, in all likelihood, plays a significant role in the formation of the cloud layer of the planet. The experiments carried out by "Venus-13,14" became an important step in the development of planetary exploration.
Related links:
ROSCOSMOS Press Release: https://www.roscosmos.ru/33167/
Venus: https://www.roscosmos.ru/tag/venera/
Images, Text, Credits: ROSCOSMOS/Orbiter.ch Aerospace/Roland Berga.
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