[X] My Assistant

[Paolo]

well this is sad but not unexpected
https://twitter.com/NASAInSight/status/1349760462854909957

One phase ends, and another begins…

Last weekend, the mole made a final attempt to dig farther underground on Mars. Even with all the steps we’ve taken to #SaveTheMole, it seems there’s just not enough friction in this soil to keep it moving downward.

[JRehling]

Ah, mole, we never had a chance to see the data you would have collected.

I hope we see a re-fly of a heat flow measurement experiment soon. I like the idea of multiple penetrators dropping from one entry vehicle, using momentum to enter the soil, and enough safety in numbers that one or more failures still lets us get one success.

This seems like something that could ride along with some future stationary lander, regardless of the lander's other functions.

https://www.lpi.usra.edu/meetings/lpsc1996/pdf/1452.pdf

[djellison]

Neither used guided entry and thus didn’t need the offset CoG. Ditto MPF, MPL, PHX and InSight.

[mcaplinger]

Neither used guided entry and thus didn’t need the offset CoG. Ditto MPF, MPL, PHX and InSight.

Actually, while Viking was unguided, it was lifting (constant lift up), not ballistic. I'm not sure how/if they managed balance for parachute deploy. Viking entered from orbit, not directly, and in the cruise phase was 3-axis stabilized, not spin-stabilized, so the less-critical cruise balance could have been managed with fixed offsets on the orbiter.

It's worth noting that avoiding the use of balance masses doesn't directly translate to more landed mass. The more landed mass, the more fuel, heavier structure, etc -- there are many ripple effects.

Similarly, penetrators IMHO are one of those things that sounds easy enough to do but turns out being harder than expected.