Venera 4 Credit - NASA

Venus probe with the announced mission of direct atmospheric studies. The descent vehicle carried two thermometers, a barometer, a radio altimeter, an atmospheric density gauge, 11 gas analyzers, and two radio transmitters operating in the DM waveband. The main bus, which carried the capsule to Venus, had a magnetometer, cosmic ray detectors, hydrogen and oxygen indicators, and charged particle traps. Signals were returned by the spacecraft, which braked and then deployed a parachute system after entering the Venusian atmosphere, until it reached an altitude of 24.96 km.

Typical orbit: 211 km x 264 km at 52 degrees inclination. Mass: 1,105 kg (2,436 lb). Associated Launch Vehicle: Molniya 8K78M.

• 1967 June 12 - Venera 4 - Program: Venera. Launch Site: Baikonur. Launch Vehicle: Molniya 8K78M. Mass: 1,104 kg (2,433 lb).

  Venera 4 was successfully launched towards the planet Venus with the announced mission of direct atmospheric studies. On October 18, 1967, the descent vehicle entered the Venusian atmosphere. Signals were returned by the spacecraft, which deployed a parachute after braking to subsonic velocity in the Venusian atmosphere, until it reached an altitude of 24.96 km.

• 1967 June 17 - Cosmos 167 - Program: Venera. Launch Site: Baikonur. Launch Vehicle: Molniya 8K78M. FAILURE: Stage 4's engine 11D33 failed to ignite because the turbopump had not been cooled before ignition. Mass: 1,106 kg (2,438 lb). Perigee: 211 km (131 mi). Apogee: 264 km (164 mi). Inclination: 51.80 deg. Period: 89.20 min.

  Suggestions for the cause of the failure included incorrect soldering of wires in multiple pin plugs, wrong attachments of the plugs to the pyrotechnic connectors, or a mix-up of the pyrotechnic connectors during assembly.. Investigation of the upper atmosphere and outer space.

• 1967 October 18 - Venera 4 Landing on Venus (USSR) -

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