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Reminds of the "Seven Minutes of Terror" video that NASA put out ahead of the Curiosity landing explaining how they intended to make it safely to the surface.

https://www.youtube.com/watch?v=Ki_Af_o9Q9s

(Note: I get goosebumps every time I watch this, absolutely amazing problem solving.)

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I'm still amazed that it succeeded. I was prepared to bet quite a bit of money that at least one of the many quite complicated stages of the landing would fail. I'm happy I was wrong.

To me, the air bags[1] used to land the Spirit and Opportunity rovers seemed like a saner way to go than trying to deposit them gently directly on to the surface using a sky crane. The reported reason the sky crane was used for Curiosity is that it was too heavy for the air bag approach.

[1] - https://www.youtube.com/watch?v=XRCIzZHpFtY

It's 185 kg vs 899 kg. I am already a bit surprised that it worked to land Spirit and Opportunity, but the lower gravity probably helps.

But the Spirit and Opportunity EDL also involved retrorockets in addition to a heatshield, a drogue chute, a parachute and the airbags - it's just that the retrorocket part didn't have to be as precise as with Curiosity.

I actually laughed the first time I saw it because it looked so much like a Goldberg machine... But it cost 500M$... And they only got one try.

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