Mercury is among the least explored planets, despite its vicinity to Earth. Just two probes have been sent to Mercury, a third one is underway and no probe landed softly on Mercury so far, Messenger just crashed onto the planet. The poles of Mercury provide for a good environment to operate a probe or rover in (and eventually for a human base).

The only celestial bodies rovers have been sent to so far are Mars (by America) and the Moon (by the Soviet Union and China). A Venus rover (Zephyr) is in concept. Why aren't there proposals on sending rovers to a planet whose surface is still unexplored from the ground? What would be any obstacles for such probe, except for being careful to not let it fall into the Sun?

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    – gerrit
    Commented Apr 23, 2021 at 14:45
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    $\begingroup$ Making stuff fall into the Sun is a hard feat (delta v needed: 30km/s). You don't have to be careful. If you lose the probe, it's in solar orbit for someone to collect later. $\endgroup$
    – Jens
    Commented Apr 23, 2021 at 17:10

3 Answers 3


This question: Calculating the delta V budget from Earth to Mercury Gives the reason. Mercury is actually very difficult to reach directly due to its location deep inside the Sun's gravitational well. Gravitational assists from Venus and Earth can help but at the cost of an extended mission duration. In addition landing on Mercury has to be propulsive as there is no significant atmosphere to brake into. So it is much harder to get to Mercury than get to Mars despite its apparent vicinity to Earth.

Apart from the serious difficulties of getting to the surface of Mercury, the conditions once there should be suitable for a base. There is water ice in some of the perpetual dark areas of craters at the poles and some nearby peaks are in virtually perpetual Sunlight. So water and plenty of energy are available as well as cooling and the surface also has a high concentration of metals.

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    $\begingroup$ There's also the little issue of the extended mission duration involving an extended time up close to the sun, with up to 10 times the solar radiation and heating exposure experienced at the distance of Earth. A polar Mercury base would be one of the most difficult locations in the solar system to actually deliver humans (or robots) to. $\endgroup$ Commented Apr 22, 2021 at 12:18
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    $\begingroup$ Yes agreed that it would be a very difficult location to reach, but once there any substantial south facing crater wall would block the Sun and present cryogenic temperatures for cooling purposes. And solar panels raised above the crater rim would sure get plenty of light. $\endgroup$
    – Slarty
    Commented Apr 22, 2021 at 12:52
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    $\begingroup$ In terms of pure delta-v, it is actually harder to get to Mercury surface than to get to Pluto surface. $\endgroup$ Commented Apr 22, 2021 at 17:10
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    $\begingroup$ I thought a read decades ago that it actually requires less fuel to get to Mars than the moon as well but I think there were caveats about how you get to Mars. $\endgroup$
    – JimmyJames
    Commented Apr 22, 2021 at 18:26
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    $\begingroup$ @JimmyJames That depends on if you want to land and if your craft can survive aerobraking. Getting to Mars flyby takes about 1km/s more dV than Moon flyby. However if you can take full advantage of the Martian atmosphere to slow you, then you can get onto the surface of Mars with about 1.5 km/s less dV than it takes to get to the surface of the Moon. $\endgroup$
    – tylisirn
    Commented Apr 22, 2021 at 20:51

I would like to add one more reason: how are you going to sell it to the budget people? Compared to Mars Mercury is in the general story line quite boring. Can anyone even suggest that there could have been life there, as the story line about Mars goes? Or, is anyone even considering setting up a Mercury camp for people? Especially as a rover on Mercury would be more expensive and higher risk than one more rover on Mars. So, just perhaps, be a bit patient and it might happen within your lifetime. Or not.

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    $\begingroup$ One reason Mercury is boring is that we know very little about it, because it's much less explored... — And, though it's true that the budget people put a lot of weight on the possibility of finding life (IMO much more than they should), they're certainly aware that the chances of this aren't super high on Mars either. $\endgroup$ Commented Apr 23, 2021 at 9:26
  • $\begingroup$ Compared to "no {...}ing way", which would have to be the verdict for Mercury... $\endgroup$
    – DevSolar
    Commented Apr 23, 2021 at 18:20

Compare the latest missions to each of the planets

Planet Mission Launch Arrival Travel
Mars Mars2020 Jul 2020 Feb 2021 7 mo
Mercury BepiColombo Oct 2018 Dec 2025 7 yr

Not only that but the BepiColombo spacecraft was heavier at launch that Mar2020 was and landing on Mercury requires much more fuel than landing on Mars so you would need an even heavier spacecraft that would probably take even more gravity assists to slow it down so it would take even longer. If we are worried about humans surviving that trip Mars, you can imaging the concern about a trip to Mercury that might take 20 times that long.

  • $\begingroup$ I am not sure why the table is not showing correctly. It looks fine in the preview $\endgroup$ Commented Jun 16, 2022 at 22:48

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