4 ms·

I'm not sure if the density plays into this too much. Gravity would probably play a bigger role as the gravity is only 38% of Earth's so it would need less wind

I'm not sure if the density plays into this too much. Gravity would probably play a bigger role as the gravity is only 38% of Earth's so it would need less wind to move

wumms 1y ago
Wind forces in the 17 mbar tests (mentioned in the article) are roughly twice as strong as those on Mars, but still about 60x weaker than on Earth at full atmospheric pressure (1013 hPa (= 1013 mbar)). The lower gravity might compensate for the pressure in the test being about twice as high.
- foobarbecue 1y ago
  Where did you find info about the pressure they tested at? I don't see it at https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DPS2025-1775.html https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DP... or https://phys.org/news/2025-09-tumbleweed-rover-technology-mars-exploration.html https://phys.org/news/2025-09-tumbleweed-rover-technology-ma...
  - wumms 1y ago
    The phys.org article mentions it: "[...] the team carried out static and dynamic tests in a wind tunnel with a variety of wind speeds and ground surfaces under a low atmospheric pressure of 17 millibars. Results showed that wind speeds of 9–10 meters per second were sufficient to set the rover in motion over a range of Mars-like terrains, including smooth and rough surfaces, sand, pebbles and boulder field."
    - foobarbecue 1y ago
      Ah, thanks, I missed that. It's weird how that information is in the phys.org article but not in the linked abstract. I guess that's because it's just an abstract -- they must have given more details during the presentation.
- IAmBroom 1y ago
  Mars gravity is 38% of Earth's. The force caused by the wind acting on the rovers are 50% of Mars, if you are correct, so I'd expect twice the "sail" force pushing the CG of the rover versus its current contact "point" on Mars as in the experiment. 2/0.38 = 2.5x the moving force. When the CG is pushed forward, the whole thing rotates, and the rover advances to a new contact point. Of course, we're talking about things like wind velocity and surface texture as "constants" here, but yeah: the thing should move.

I'm not sure if the density plays into this too much. Gravity would probably play a bigger role as the gravity is only 38% of Earth's so it would need less wind to move

wumms 1y ago

Wind forces in the 17 mbar tests (mentioned in the article) are roughly twice as strong as those on Mars, but still about 60x weaker than on Earth at full atmospheric pressure (1013 hPa (= 1013 mbar)). The lower gravity might compensate for the pressure in the test being about twice as high.

foobarbecue 1y ago
Where did you find info about the pressure they tested at? I don't see it at https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DPS2025-1775.html https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DP... or https://phys.org/news/2025-09-tumbleweed-rover-technology-mars-exploration.html https://phys.org/news/2025-09-tumbleweed-rover-technology-ma...
- wumms 1y ago
  The phys.org article mentions it: "[...] the team carried out static and dynamic tests in a wind tunnel with a variety of wind speeds and ground surfaces under a low atmospheric pressure of 17 millibars. Results showed that wind speeds of 9–10 meters per second were sufficient to set the rover in motion over a range of Mars-like terrains, including smooth and rough surfaces, sand, pebbles and boulder field."
  - foobarbecue 1y ago
    Ah, thanks, I missed that. It's weird how that information is in the phys.org article but not in the linked abstract. I guess that's because it's just an abstract -- they must have given more details during the presentation.
IAmBroom 1y ago
Mars gravity is 38% of Earth's. The force caused by the wind acting on the rovers are 50% of Mars, if you are correct, so I'd expect twice the "sail" force pushing the CG of the rover versus its current contact "point" on Mars as in the experiment. 2/0.38 = 2.5x the moving force. When the CG is pushed forward, the whole thing rotates, and the rover advances to a new contact point. Of course, we're talking about things like wind velocity and surface texture as "constants" here, but yeah: the thing should move.