Mars 5
Mars 5 — a Soviet orbiter, in Mars orbit from 12 February 1974. A slow loss of pressure aboard gave it only about two weeks, in which it photographed the region south of Valles Marineris; its pictures showed signs of erosion by flowing water. Last contact was on 28 February 1974.
Key facts
Mission & specifications
Mission
- Operator
- Lavochkin (USSR)
- Launched
- July 25, 1973
- Status
- Completed
Trajectory
- Distance from the Sun
- 1.58 AU
- Computed from the cached position
- Distance from Earth
- 1.55 AU
- Computed from cached positions
- Distance from Mars
- 4,533,221 km
- Computed from cached positions
Mission
Mars 5 was Mars 4's sister orbiter, and the only one of the four Soviet Mars craft of 1973 to reach Mars orbit. It fired its engine at 15:44:25 UT on 12 February 1974 and settled into a 1,755 × 32,555 km orbit, circling once every 24 hours and 53 minutes. Almost at once, controllers saw that it was slowly losing pressure — NSSDCA says in its transmitter housing, NASA's history Beyond Earth in its main instrument compartment, probably after a particle struck it. With only weeks left, scientists drew up a hurried programme. In five imaging sessions between 17 and 26 February its two cameras photographed the region south of Valles Marineris; the sources count the usable pictures differently, NSSDCA about 60 and Beyond Earth 43 of 108 frames. Some rivalled those of NASA's Mariner 9 and showed features carved by flowing water. Its other instruments found a thin ozone layer about 40 km up, water vapour south of the Tharsis region and surface temperatures up to 272 K (−1 °C). The last session, on 28 February 1974, sent back a final panorama. Mars 5 was meant to relay the signals of the Mars 6 and 7 landers the following month, and could not.
- 1973Mars 5 launches toward Mars on a Proton rocketLaunch
Mars 4's sister orbiter sets out four days behind it.
And soon begins slowly losing pressure.
- 1974A hurried imaging campaignMilestone
Five sessions photograph the region south of Valles Marineris.
- 1974Last contactMission end
A final panorama, then the pressure aboard falls too low.
Images
Images from open archives · credit shown per image