Mission Type: Lander
Launch Vehicle: Modified SS-6 (Sapwood) with second-generation upper stage + escape stage; 8K78M
Launch Site: Tyuratam (Baikonur Cosmodrome), USSR
Spacecraft Mass: 1180 kg
Bus: 1) solar wind detector and 2) cosmic-ray detector
Lander: 1) resistance thermometer and 2) aneroid barometer
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
National Space Science Data Center, http://nssdc.gsfc.nasa.gov/
Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.
Venera 7 was one of a pair of spacecraft prepared by the Soviets in 1970 to make a survivable landing on the surface of Venus. The spacecraft were quite similar in design to Veneras 4, 5, and 6, with a main bus and a spherical lander (now with a mass of 500 kilograms). After the last mission, engineers redesigned the landing capsule to withstand pressures of up to 180 Earth atmospheres and temperatures of up to 540 degrees Celsius.
Venera 7 successfully left Earth orbit and implemented two midcourse corrections on 2 October and 17 November, respectively, before beginning its Venus encounter operations on 12 December 1970, when the lander probe's batteries were charged up (using solar panels on the bus) and the internal temperature lowered. At 04:58:44 UT on 15 December, the lander separated from the bus and entered the Venusian atmosphere at an altitude of 135 kilometers and a velocity of 11.5 kilometers per second. When aerodynamic drag had reduced velocity to 200 meters per second at an altitude of 60 kilometers, the parachute system deployed. Within 35 minutes, at 05:34:10 UT, the capsule was on the Venusian landscape.
Although transmissions appeared to have ended at the moment of landing, Soviet ground tracking stations recorded what at first proved to be unintelligible noise. After computer processing of the data, Soviet scientists discovered a valuable 22 minutes 58 seconds of information from the capsule-the first transmissions of a spacecraft from the surface of another planet. Quite likely, the initial loss of signal occurred when the capsule tipped over on its side. Venera 7's data indicated a surface temperature of 475 give or take 20 degrees Celsius and a pressure of 90 give or take 15 atmospheres. The information was a good fit with previous Soviet and American estimates. Impact point was 5 degree; south latitude and 351degree longitude.