The question Wheels vs. tracks for rovers and Does new technology make it advantageous to have walking rovers? ask about the possible use of treads or legs instead of wheels on rovers from a speculative point of view.

But which rover already on another solar system body didn't have any wheels?


The list of successful rover missions is short:

  • Moon: LRV, Lunokhod, Yutu
  • Mars: Sojourner, Spirit, Opportunity, Curiosity

All of them have wheels.

The Soviet Union built two walking rovers (using 2 skis) (Prop-M), for the Mars-2 and Mars-3 missions. Both missions failed before these rovers could be deployed.

  • $\begingroup$ Yep, they are indeed wheel-less rovers that are on Mars, but as you point out, probably not successfully deployed from their landers, although I don't know if that is absolutely certain in both cases, or just highly likely. $\endgroup$ – uhoh May 29 '17 at 15:34
  • $\begingroup$ Can I get you to change "None" to something more accurate? There are in fact two Prop-M rovers on mars, correct? They were probably not deployed, nor did they rove, but there are still two wheel-less rovers on Mars. It's not like the rocket blew up on the launch pad or something. $\endgroup$ – uhoh May 30 '17 at 5:05
  • $\begingroup$ According to Wikipedia,The (Mars 2) descent module became the first man-made object to impact the surface of Mars, and ...the (Mars 3) lander achieved a soft landing at 45°S 202°E and began operations. and there appears to be independent photographic evidence of the lander, retro-rockets, heat shield and parachute. $\endgroup$ – uhoh May 30 '17 at 5:06
  • $\begingroup$ Radio contact with Mars 3 was lost, that can be considered a mission failure. But I'm still looking for an answer to Is there any chance Mars-3's Prop-M rover deployed automatically and “roved”? $\endgroup$ – uhoh May 30 '17 at 7:13
  • $\begingroup$ OK @called2voyage has removed any lingering uncertainty. Without radio contact from Earth, the Prop-M rover would not be deployed. There are two on Mars, one in a crash landing, one in landing that went as expected, but not deployed. You may want to link to his answer here, it's a good one! $\endgroup$ – uhoh Jun 1 '17 at 14:04

Looks like @Hobbes nailed it right off with this answer. There are two Prop-M rovers on Mars. While Mars-2 crash-landed, Mars-3 landed and began transmitting. However, thanks to some excellent research by @called2voyage, we can see that because the rovers would not be deployed without explicit radio instruction, neither rovers were ever able to "rove" on Mars. Nevertheless it seems they are there, in some form or other.

I'll have to think of something harder for a puzzler next time.

I'll add this cute GIF and photo, both found at the Wikipedia article for Mars 3. According to the article, the rover was to remain attached by an umbilical to the lander, and do some local exploration while monitored and sometimes filmed by the lander.

enter image description here

above: GIF of how the Prop-M rover uses it's "skis" to walk. Linked here, from Giphy.

enter image description here

above: Mars Prop-M rover from here.


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