Venera program: Soviet Venera 6 begins its descent into the atmosphere of Venus, sending back atmospheric data before being crushed by pressure.
Venera 6 (Russian: -6 meaning Venus 6), or 2V (V-69) No.331, was a Soviet spacecraft, launched towards Venus to obtain atmospheric data. It had an on-orbit dry mass of 1,130 kg (2,490 lb).
The spacecraft was very similar to Venera 4 although it was of a stronger design. When the atmosphere of Venus was approached, a capsule with a mass of 405 kilograms (893 lb) was jettisoned from the main spacecraft. This capsule contained scientific instruments.
During descent towards the surface of Venus, a parachute opened to slow the rate of descent. For 51 minutes on May 17, 1969, while the capsule was suspended from the parachute, data from the Venusian atmosphere were returned. It landed at 5S 23E.
The spacecraft also carried a medallion bearing the State Coat of Arms of the Soviet Union and a bas-relief of Lenin to the night side of Venus.
Given the results from Venera 4, the Venera 5 and Venera 6 landers contained new chemical analysis experiments tuned to provide more precise measurements of the atmosphere's components. Knowing the atmosphere was extremely dense, the parachutes were also made smaller so the capsule would reach its full crush depth before running out of power (as Venera-4 had done).
The Venera (Russian: Вене́ра, pronounced [vʲɪˈnʲɛrə], which means "Venus" in Russian) program was the name given to a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus. Ten probes successfully landed on the surface of the planet, including the two Vega program and Venera-Halley probes, while thirteen probes successfully entered the Venusian atmosphere. Due to the extreme surface conditions on Venus, the probes could only survive for a short period on the surface, with times ranging from 23 minutes to two hours.
The Venera program established a number of precedents in space exploration, among them being the first human-made devices to enter the atmosphere of another planet (Venera 3 on 1 March 1966), the first to make a soft landing on another planet (Venera 7 on 15 December 1970), the first to return images from another planet's surface (Venera 9 on 8 June 1975), the first to record sounds on another planet (Venera 13 on 30 October 1981), and the first to perform high-resolution radar mapping scans (Venera 15 on 2 June 1983).