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What would happen if a Mars rover (let it be Sojourner, Spirit, Opportunity, Curiosity or Perseverance) would be sent to the Moon instead of the Mars? Let's not deal with the landing and let's assume the rover has just landed safely and has its wheels on the ground. How good or bad would it be doing? Which systems would behave correctly and which would fail and thus need a redesign? How long would the rover approximately last?

Looks like the first candidate for failure would probably be the thermal control since Moon and Mars have different temperature profiles. I also guess rovers with RTG may survive lunar night easier since they could heat themselves even in the darkness.

Kozuch
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NASA would never, ever send a rover designed to operate on Mars to the Moon. The Moon and Mars are very different environments. A rover designed to operate on the Moon might be designed to operate on the surface of the Moon

  • For just a few days and then die,
  • For 14 days (the length of daytime on the Moon, except near the poles) and then die, or
  • For a long, long time before it dies.

These three options have distinct design impacts, none of which are met by the Mars rovers.

The first option (a few days) means a rather cheap rover. There would be no reason to send one of those very expensive Mars rovers to the Moon but then expect it to die within a few days. Some of NASA's Commercial Lunar Payload Services (CLPS) options involve a rover that is expected to last only a few days. The amount NASA will pay for such rovers is not even close to the cost of a Mars rover.

The second option (14 days, not at the poles) requires a rover that can withstand significantly higher surface temperatures than the Mars rovers can withstand. This is a significant design change from the Mars rovers. The wheels on the Mars rovers are not designed to handle surface temperatures over 100 °C, and the bodies of the Mars rovers are not designed to handle to much more intense sunlight on the surface of the Moon than occurs on the surface of Mars. This is once again a significant design change from the Mars rovers.

The third option, a lunar rover that lasts a long time, requires a rover that can withstand both significantly higher and significantly lower surface temperatures than the Mars rovers can withstand, and corresponding sustained periods of lack of sunlight and radiation by the rover body to empty space at 2.7 kelvins. This yet again represents a significant design change from the Mars rovers.

David Hammen
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    Thanks for answer. I did not request NASA to send Mars rover to Moon though and I of course understand no one would ever do this. This is theoretical question whose answers should show the difference between Mars and Moon. – Kozuch Mar 11 '21 at 16:33
  • @Kozuch The differences between sending a semi-autonomous vehicle to the Moon versus sending a semi-autonomous vehicle to Mars are so vast that it just does not make any sense at all to send a rover explicitly designed to operate on Mars to the Moon, with no changes in design at all. Sorry to be so blunt. – David Hammen Mar 11 '21 at 17:23
  • I did not even address at all the vast difference in the round trip time between observations from a rover on Mars to Earth, reactions by controllers on the Earth, commands issued from the Earth to that Mars rover, and receival / response by the Mars rover, versus the same for a rover on the Moon. A huge amount of the autonomy that is absolutely essential for a successful Mars rover would not be needed for a Moon rover. – David Hammen Mar 11 '21 at 17:36
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    @Kozuch There would be no reason to send a rover designed for Mars to the Moon without huge design changes. None, zilch, zero, nada. Once again, sorry to be so blunt. This might be a potential personal problem (do I have too narrow a vision?), but I'll be retiring soon, so you can soon say goodbye to my hardcore engineer idiosyncrasies. But I do hope that before I retire I will have trained a sizeable cadre younger engineers to have the same hardboiled problems with regard to theoretical questions. I've been working on that problem (transferring my knowledge) for several years. – David Hammen Mar 11 '21 at 17:40
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    Note well: My degree is in physics. I am not nearly as hard-boiled as those who were hard-boiled as engineering students in their early twenties. Those truly hard-boiled people wouldn't even begin to answer this question. – David Hammen Mar 11 '21 at 17:47
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    Being blunt is completely your thing but I am just saying it is absolutely not needed here. Of course no one would do what I asked about, but the point here is to thoroughly explain why no one would do it and explain it with proper factual reasoning. Period. :) – Kozuch Mar 11 '21 at 17:48
  • @Kozuch I was blunt in my comments, but not in my answer. Comments can and oftentimes do disappear. From my perspective, you might as well have asked what would happen to a Mars rover if was sent to Venus. The answer is simple: It would die. Quickly. Because of that, no one sane would even think of sending a Mars rover to Venus, or to the Moon for that matter. – David Hammen Mar 11 '21 at 22:41
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    This is an excellent answer to the question "would NASA send a mars rover to the moon?". However, the question here is a different one. As you noted in a comment the short answer is "it would die". The question is asking "how would it die - what systems would fail first". What's the long answer? – Dan Pichelman Mar 12 '21 at 16:15