Launched on June 12th, 1967, Venera 4 was the first Russian probe to reach Venus still working. The previous 3 probes failed prior to arrival. Venera 4 had 2 sections:
The main bus, weighing 723kg, was to fly right at Venus and scan it's atmosphere, magnetic field, hydrogen halo and the solar wind using the following instruments:
- Triaxial Fluxgate Magnetometer
- 4 Ion Traps
- STS-5 Gas-Discharge Counter
- 2 Silicon Solid-State Radiation Detectors
- Windowed SBT-9 Gas-Discharge Counter
- Lyman-α Atomic Hydrogen & Oxygen Spectrometers
After it hit the atmosphere, October 18th, 1967, the bus was to drop the capsule and disintegrate. All went according to plan and the probe discovered that Venus has a weak magnetic field (3000x < Earth), no radiation field and a weak hydrogen corona (1000x < Earth).
- Thermal Control (to keep capsule at -8°C)
- Set of gas analysis instruments.
The parachute deployed at 52km above the surface where it read a little less than 1 atmosphere and 33°C. The transmissions stopped at about 26km above the surface where it read 22 atmospheres and 262°C. The probe found that the atmosphere contained almost no Hydrogen or Oxygen (0.4-0.8%), very little Nitrogen (7%) and mostly Carbon Dioxide (90-93%). The altimeter malfunctioned reading the capsule 26km lower than it actually was.
The capsule also included durable penants on the spacecraft (above right). It was kind of like putting a flag on Venus.