Venera 7 sent the first data from another planet's surface
On this day · 15 December 1970
On 15 December 1970 Venera 7 crashed onto Venus after its parachute failed — and its 23-minute signal was only found later in the recordings.
The Soviet probe Venera 7 became the first spacecraft to transmit data from the surface of another planet on 15 December 1970, sending a faint signal from Venus for about 23 minutes after it hit the ground. It had been launched on 17 August 1970.
Was it really a soft landing?
NASA’s list of space firsts credits Venera 7 with the first soft landing on Venus, but the descent was anything but gentle. Its parachute ripped and collapsed, leaving the probe to fall for 29 minutes before it slammed into the surface. It probably bounced and came to rest on its side, with its antenna no longer aimed at Earth.
At first the probe seemed to have gone silent on impact. Only later analysis of the recorded radio signals revealed the 23 minutes of weak transmission from the ground; with the descent, Venera 7 sent about 53 minutes of signals in all. “Landing” is fair; “soft” is generous. What counted was that the probe survived.
The readings were brutal: about 475 °C and a pressure of roughly 92 bar, around 90 times Earth’s at sea level, with a light wind of 2.5 metres per second. During the descent it had measured an atmosphere about 97% carbon dioxide. NASA’s modern figure for Venus’s surface is about 467 °C, hot enough to melt lead, so the single reading from 1970 holds up well.
Venera 7 was the lucky one of two. The Soviet Union launched a second Venus lander, Cosmos 359, on 22 August 1970, but it failed to leave Earth orbit.
Venus yielded its first surface photographs to Venera 10 in October 1975, and its first colour pictures to Venera 13 in March 1982.
Sources & references
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