Mission Type: Lander
Launch Vehicle: Modified SS-6 (Sapwood) with second-generation upper stage + escape stage; 8K78M
Launch Site: NIIP-5 / launch site 31; Tyuratam (Baikonur Cosmodrome), USSR
Spacecraft Mass: 1184 kg at launch, 495 kg landing capsule
Bus: 1) cosmic-ray detector; 2) solar wind detector; and 3) ultraviolet spectrometer
Lander: 1) thermometer; 2) barometer; 3) radio altimeter; 4) photometer; 5) gamma-ray spectrometer; 6) gas analyzer; and 7) wind-speed recorder
Spacecraft Power: Solar panels; batteries
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 8 was the first in another pair of Soviet spacecraft designed to explore Venus. Although similar in design to its predecessors, the 495-kilogram lander was substantially modified, based on the results from Venera 7. The new capsule was designed to withstand pressures of "only" 105 atmospheres (versus 180 atmospheres on Venera 7) and carried extra scientific instrumentation.
After one midcourse correction on 6 April 1972, Venera 8's lander separated from the flyby bus and entered the Venusian atmosphere at 08:37 UT on 22 July 1972 at a velocity of 11.6 kilometers per second. Successful landing took place at 09:32 UT, about 500 kilometers from the morning terminator on the sunlit side of Venus. Landing coordinates were 10° south latitude and 335°longitude.
The probe transmitted data for another 50 minutes 11 seconds from the hostile surface before succumbing to ground conditions. The transmitted information indicated that temperature and pressure at the landing site were 470 give or take 8°C and 90 give or take 1.5 atmospheres respectively. Wind speed was less than 1 kilometer per second below 10 kilometers altitude. The spacecraft also recorded a sharp change in illumination between 30 and 35 kilometers altitude. The data indicate that visibility on the ground was about one kilometer at the time Venera 8 landed.