Considering Mars' mean atmospheric pressure of 610 Pa (0.088 psi) its "sea level altitude", how high went the highest probe/rover that ever successfully landed on Mars so far (respectively, what's the lowest atmospheric pressure a probe on the Martian surface has ever been in), and how low/deep the lowest one (or what's the highest pressure a probe/rover has been in)?
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I combed through Wikipedia's list of Mars missions and found all of the successful landers/rovers and included the Chinese Tianwen-1 though it has not landed successfully as of this answer. I got the elevations using Google Earth Pro which has an option to view Mars and uses MOLA data from the Mars Global Surveyor. I cross-checked the InSight one with the official value from 2018 MARS INSIGHT TRAJECTORY RECONSTRUCTION AND PERFORMANCE FROM LAUNCH THROUGH LANDING and it was correct:
| Spacecraft / Mission: | Latitude (°, N+): | Longitude (°, E+): | Elevation (m) | Visible on Google Earth Pro? |
|---|---|---|---|---|
| Mars 3 | -45 | 202 | 1654 | no |
| Viking 1 | 22.27 | 312.05 | -3637 | yes |
| Viking 2 | 47.667569 | -225.715758 | -4451 | yes |
| Mars Pathfinder | 19.098 | -33.25 | -3682 | yes |
| Spirit / MER-A | -14.5684 | 175.472636 | -1945 | yes |
| Opportunity / MER-B | -1.9462 | 354.4734 | -1373 | yes |
| Phoenix | 68.2188 | -125.7492 | -4128 | yes |
| Curiosity / MSL | -4.5895 | 137.4417 | -4447 | no |
| InSight | 4.5024 | 136.6234 | -2613 | no |
| Perseverance / Mars 2020 | 18.4446 | 77.4509 | -2564 | no |
| Tianwen-1 | 24.748 | 110.318 | -4040 | no |
Elevations are relative to the MOLA geoid/areoid/equipotential surface. Locations taken from Wikipedia for all (less Tianwen-1), modified for some to place exactly on spacecraft in Google Earth Pro.
Wikipedia also has this nice graphic:
answered May 7, 2021 at 16:47
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$\begingroup$ Thank you. Mars 3 doesn't have a sharp image, so the highest "proper" mission is Opportunity so far. However, I dunno what is used as "elevation" on Google Mars and on WP's map. Hopefully, both are according to pressure rather than vale-to-peak altitudes. But I guess they probably are oriented on pressure altitude, or on mean radius which would be about the same. $\endgroup$– GiovanniMay 7, 2021 at 17:10
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$\begingroup$ @Giovanni they used to define 'zero-elevation' as a pressure but switched to a more consistent definition, see Areoid and Mars Zero Elevation $\endgroup$ May 7, 2021 at 17:22
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$\begingroup$ So mean radius since 2001. However, as the Earth's sea level is defined at a certain pressure (29.92 inHg), the same method should be used on all celestial bodies with atmospheres. Or alternatively, the Earth's 0 altitude be defined as its mean radius. $\endgroup$– GiovanniMay 7, 2021 at 17:53
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$\begingroup$ @Giovanni you might find section 7.5 of Mars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars, Smith et al. interesting $\endgroup$ May 7, 2021 at 18:57
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