Mariner 5
Mariner 5 — NASA/JPL's Venus flyby of 19 October 1967, rebuilt from Mariner 4's flight spare. Carrying no camera, it swept about 4,000 km past Venus and used radio occultation and field/particle instruments to probe the crushing CO₂ atmosphere, find a hydrogen corona, and show Venus has essentially no magnetic field yet still deflects the solar wind.
Key facts
Mission & specifications
Mission
- Operator
- NASA / JPL
- Launched
- June 14, 1967
- Status
- Completed
Trajectory
- Distance from the Sun
- 0.726 AU
- Computed from the cached position
- Distance from Earth
- 0.348 AU
- Computed from cached positions
- Distance from Venus
- 0.122 AU
- Computed from cached positions
Mission
Mariner 5 was a mission of thrift and ingenuity — built from the spare parts of an earlier flight and turned to an entirely new target. Originally a backup for Mariner 4's 1964 Mars flyby, the leftover spacecraft was rebuilt to study Venus instead, its heat shielding reworked for a mission toward the Sun rather than away from it. Launched on 14 June 1967, it swept about four thousand kilometres past Venus on 19 October. It carried no camera; this was a mission of invisible senses. As the spacecraft passed behind the planet, engineers watched its radio signal bend and fade through the atmosphere, and from that occultation — with its ultraviolet and particle instruments — Mariner 5 measured the crushing density of Venus's carbon-dioxide air, detected a tenuous hydrogen corona, and showed that Venus has essentially no magnetic field of its own yet still carves a bow shock in the solar wind. It sharpened the emerging, forbidding portrait of Venus as a world utterly unlike Earth.
- 1967Rebuilt for VenusLaunch
Mariner 4's flight spare, reworked from a Mars to a Venus mission, launches on an Atlas-Agena.
Carrying no camera, it uses radio occultation and field instruments to probe the CO₂ atmosphere and confirm Venus lacks a magnetic field.
- 1968Contact endedMission end
After a brief re-acquisition in October 1968, contact attempts are formally ended.
Images
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