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The more impressive part is that the sky crane shot pictures, video and data and had to download everything to the rover before it was cut loose. As soon as the

by donarb 6y ago

The more impressive part is that the sky crane shot pictures, video and data and had to download everything to the rover before it was cut loose. As soon as the rover wheels touched ground, the tether was cut and the lander flew away.

rtkwe 6y ago
That's relatively simple just wire them directly into the rover to start with so the data is always in the right place.
HarHarVeryFunny 6y ago
I'd like to know how they cut/released the tether, and if there's any fallback in case 1st release attempt fails. The entire mission is fucked if the tether release failed, or if the sky crane tries to fly away while still tethered.
- donarb 6y ago
  They use explosive bolts that attach the tether to the deck of the rover. They're almost 100% fool proof. Here's a Wikipedia entry, they're called pyrotechnic fasteners and NASA uses a lot of them. https://en.wikipedia.org/wiki/Pyrotechnic_fastener https://en.wikipedia.org/wiki/Pyrotechnic_fastener
  - polishdude20 6y ago
    But the image of the cables show what looks to actually be a literal cut cable. Not just a connector being disconnected but a clean slice.
    - snarf 6y ago
      From today's Reddit AMA with the NASA team, they use pyrotechnics to set off a guillotine like device to cut the cables. Possibly something like https://psemc.com/products/pyrotechnic-cable-cutter/ https://psemc.com/products/pyrotechnic-cable-cutter/ Source: https://www.reddit.com/r/IAmA/comments/lpzbzo/were_scientists_and_engineers_working_on_nasas/godvks8?utm_source=share&utm_medium=web2x&context=3 https://www.reddit.com/r/IAmA/comments/lpzbzo/were_scientist...
- Ductapemaster 6y ago
  I don't know how they achieved it specifically, but there is a moment in the broadcast[0] they did where they show the umbilical on the rover and mention that it was cut. I'm curious as well how they did it! [0] https://youtu.be/gYQwuYZbA6o?t=1898 https://youtu.be/gYQwuYZbA6o?t=1898

by donarb 6y ago

rtkwe 6y ago

That's relatively simple just wire them directly into the rover to start with so the data is always in the right place.

HarHarVeryFunny 6y ago

I'd like to know how they cut/released the tether, and if there's any fallback in case 1st release attempt fails. The entire mission is fucked if the tether release failed, or if the sky crane tries to fly away while still tethered.

donarb 6y ago
They use explosive bolts that attach the tether to the deck of the rover. They're almost 100% fool proof. Here's a Wikipedia entry, they're called pyrotechnic fasteners and NASA uses a lot of them. https://en.wikipedia.org/wiki/Pyrotechnic_fastener https://en.wikipedia.org/wiki/Pyrotechnic_fastener
- polishdude20 6y ago
  But the image of the cables show what looks to actually be a literal cut cable. Not just a connector being disconnected but a clean slice.
  - snarf 6y ago
    From today's Reddit AMA with the NASA team, they use pyrotechnics to set off a guillotine like device to cut the cables. Possibly something like https://psemc.com/products/pyrotechnic-cable-cutter/ https://psemc.com/products/pyrotechnic-cable-cutter/ Source: https://www.reddit.com/r/IAmA/comments/lpzbzo/were_scientists_and_engineers_working_on_nasas/godvks8?utm_source=share&utm_medium=web2x&context=3 https://www.reddit.com/r/IAmA/comments/lpzbzo/were_scientist...
Ductapemaster 6y ago
I don't know how they achieved it specifically, but there is a moment in the broadcast[0] they did where they show the umbilical on the rover and mention that it was cut. I'm curious as well how they did it! [0] https://youtu.be/gYQwuYZbA6o?t=1898 https://youtu.be/gYQwuYZbA6o?t=1898