Venera 7

The Venera 7 (Russian: Венера-7) (manufacturer's designation: 3V (V-70)) was a Soviet spacecraft, part of the Venera series of probes to Venus. When it landed on the Venusian surface, it became the first man-made spacecraft to land successfully on another planet, and to transmit data from there back to Earth.

The probe was launched from earth on the August 17, 1970 at 05:38 UTC. It consisted of an interplanetary bus based on the 3MV system and a lander. During the flight to Venus two in course corrections were made using the bus's on-board KDU-414 engine.

It entered the atmosphere of Venus on December 15, 1970. Unusually the lander remained attached to the interplanetary bus during the initial stages of atmospheric entry. This was to allow the bus to cool the lander to -8°C for as long as possible. The lander was ejected once atmospheric buffeting broke the interplanetary bus's lock-on with earth. The parachute opened at a height of 60 km and atmospheric testing began with results showing the atmosphere to be 97% carbon dioxide. During the descent the parachute appeared to fail, resulting in a more rapid than planned decent. As a result the lander impacted with the surface of Venus at about 16.5 m/s at 05:37:10 UTC. Landing coordinates are 5°S 351°E / 5°S 351°E / -5; 351.

The probe appeared to go silent on impact. However, recording tapes kept rolling. A few weeks later, upon a reviewing of the tapes, another 23 minutes of very weak signals were found on them. The spacecraft had landed on Venus, probably bounced onto its side on landing, and the medium gain antenna was not pointed correctly for strong signal transmission to Earth. The only data returned from the surface was temperature data, which gave a reading of 475°C.