1 mo. ago • 100%

Dragon can now use SuperDracos if parachutes fail

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Steve Stich states at today's Crew-9 news conference that Dragon has a new contingency capability if all 4 parachutes fail; the SuperDracos will ignite prior to splashdown.

The Crew-8 return to Earth will also have this capability.

(He said this about 20 minutes after the start of the stream.)

6 comments

At 52:05, Stephen Clark asked about this. The start of Gerst's answer is:

We've actually flown it on several other dragon flights before this. This is the first time it flies on a NASA mission.

So, perhaps Inspiration 4? Presumably Polaris Dawn? And I guess the Axiom missions are being counted as non-NASA in this context, so some of those?

Before doing something like this I think you should ensure that it reduces the overall risk to the crew. So you'd need to have an estimate of how likely it is that all the parachutes fail, and how likely it is that the SuperDracos could save lives in that situation, but also an estimate of how likely this capability is to go wrong. For example, could there be a bug in the software or in some sensor(s), that causes the SuperDracos to fire when they weren't needed? Would the SuperDracos otherwise be in an inactive state during re-entry, and if so, what are the risks of having them active? Etc..

Those 2 sentences from Gerstenmaier suggest to me that SpaceX had already decided that, on balance, this capability should be enabled. Whereas NASA have only just reached that conclusion.

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Any video of them testing this? Sounds really cool

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- Not really. There's a hover test vid uploaded in 2016 but they cheated. (It's held up by a rope!)
  
  Or you could play the first 17 seconds of the pad abort test in reverse ...
  
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  Animation of a 'land landing': https://youtu.be/Cf_-g3UWQ04?t=1m32s
  
  6
When composing the title of this post I nearly called this technique 'Propulsive Splashdown', but I didn't remember ever hearing that term used before. (Stitch didn't call it that, did he?)

Later I heard Stephen Clark use that term in his question. And yesterday that term was used during the launch stream. Nail and Cardman spent a minute discussing the capability: https://www.youtube.com/live/SKXtysRx0b4?t=3h29m8s (from 3:29:08)

Apparently they often abbreviate it to "prop splash".

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I like SpaceX's Sarah Walker, despite (or partly because of?) the fact that she tends not to answer questions from mere mortals (non-SpaceX / non-NASA personnel).

For example, at the Post-Launch News Conference, there was a question about pulsive splashdown (although that term was not used).

She seemed to imply that the capability would have been available for Crew-7 if it wasn't for a problem with one of the GPS sensors. (Was this problem known about well in advance of undocking? Would that be why they didn't announce the new capability at the time?)

She spent most of the time confirming the point I made in my first comment on this post, about taking into account any extra risks that this capability might add, and she said that it had taken "years".

She didn't answer whether it's available if the parachutes fail during a launch abort, nor tell us any of the (non-NASA) missions it has been active for (of which Gerst had said there were "several").

Here's the question: https://www.youtube.com/live/wwhfph1vGdE?t=32m30s (at 32:30)

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