NSSDCA/COSPAR ID: 1967-058A
Venera 4 was designed with the announced scientific objective of in-situ studies of the atmosphere of Venus down to the surface. It was the first probe to transmit data from the atmosphere of another planet.
Venera 4 consisted of a 3.5 meter high main bus carrying a 383 kilogram lander probe with vital instruments encased in a pressure vessel. The probe was designed to withstand high temperatures, pressures, and accelerations. The bus was powered by 2.5 square meters of solar panel "wings" with a span of 4 meters. A cone-shaped omni-directional antenna was mounted at the end of one of the solar panels. There was a large rocket for mid-course maneuvering, and a set of smaller thrusters for attitude control. Communications from the probe were achieved by two 922 MHz, 1 bit/sec transmitters in the DM waveband. The probe was protected by a heatshield and carried a radar device and parachutes for descent. The probe 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 had carried the capsule to Venus, carried a magnetometer, cosmic ray detectors, hydrogen and oxygen indicators, and charged particle traps.
Venera 4 was launched from a Tyazheliy Sputnik (67-058B) on 12 June 1967. After a mid-course correction on 29 July, the probe was released from the bus and entered the nightside Venusian atmosphere on October 18, 1967, at 04:34 UT. The main bus entered the atmosphere behind the probe but was not designed to survive entry. The probe initially braked using a thick ablative heatshield. At a velocity of 1032 km/hr the 2.2 meter drogue parachute was deployed, followed by a 55 meter main parachute at an altitude of 52 km. The scientific instruments had been turned on 5 minutes after separation at an altitude of about 55 km and remained on for 93 minutes, returning 23 sets of readings, until it reached an altitude of roughly 25 km, where it succumbed to the atmospheric pressure (22 bar) and temperature (277 C). The probe was over the Eisila region at approximately 19 degrees N, 38 degrees E.
The probe measured an atmospheric composition of 90 - 95% carbon dioxide. The bus detected no magnetic field or radiation belts and a weak finding of atomic hydrogen at 9900 km altitude. It was initially believed that the probe had reached the ground and the measured temperature and pressure represented the surface values on Venus.
Spacecraft images for illustrative purposes - not necessarily in the public domain.
Launch Date: 1967-06-12
Launch Vehicle: Modified SS-6 (Sapwood) with 2nd Generation Upper Stage + Escape Stage
Launch Site: Tyuratam (Baikonur Cosmodrome), U.S.S.R
Mass: 1106 kg
Questions and comments about this spacecraft can be directed to: Dr. David R. Williams
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