The Mariner 5 spacecraft was the fifth in a series of spacecraft used for planetary exploration in the flyby mode. Mariner 5 was a refurbished backup spacecraft for the Mariner 4 mission and was converted from a Mars mission to a Venus mission. The spacecraft was fully attitude stabilized, using the sun and Canopus as references. A central computer and sequencer subsystem supplied timing sequences and computing services for other spacecraft subsystems. The spacecraft passed 4,000 km from Venus on October 19, 1967. The spacecraft instruments measured both interplanetary and Venusian magnetic fields, charged particles, and plasmas, as well as the radio refractivity and UV emissions of the Venusian atmosphere. The mission was termed a success. Total research, development, launch, and support costs for the Mariner series of spacecraft (Mariners 1 through 10) was approximately $554 million.
Mariner 5 found no radiation belts trapped by Venus’ magnetic field. The ultraviolet photometer detected a hydrogen corona (as did the Soviet Venera 4), but no oxygen emission. Mariner 5’s instruments indicated that the planet’s surface temperature and pressure were 527°C and 75 to 100 atmospheres respectively. The ultraviolet photometer showed that the upper atmosphere was cold, 325°K.
On December 4, 1967, NASA lost contact with the spacecraft, although controllers briefly regained contact on October 14, 1968. The spacecraft did not transmit any further telemetry, and NASA eventually stopped attempts to communicate with the vehicle, now in heliocentric orbit.
- Ultraviolet Photometer
- Ultraviolet Photometer Principal Investigator, Charles A Barth
The objective of the Ultraviolet Photometer was to study the properties of Venus’ upper atmosphere by obtaining measurements of the ultraviolet emissions from resonance scattering of solar radiation by atmospheric atoms. The densities of the atmospheric species, and the temperature of the high atmosphere could be determined from the measurements and from the variation of the measured densities with height above the surface.
Launch date: June 14, 1967
Launch location: Cape Canaveral, Florida
Launch vehicle: Atlas-Agena D
Mission target: Venus flyby
Mission duration: 4 months
Other key dates:
- Venus flyby: October 19, 1967
Other organizations involved:
- NASA Jet Propulsion Laboratory (JPL)