Launch News SpaceX Dragon V2 Pad Abort Test, May 6, 2015

[N_Molson]

What would happen if the trunk were released after chute deploy ?

Could the chutes handle that extra mass at full deployment ?

 

[Donamy]

Wouldn't have to wait for full deploy, just stablization.

---------- Post added at 12:08 AM ---------- Previous post was at 12:04 AM ----------

On second thought, the back of the trunk isn't very aerodynamic.

 

[Thunder Chicken]

Looks like a more or less successful abort, but the tumbling during parachute deployment is extreme, I doubt that this would not kill astronauts by breaking their neck.

I think the astronauts would be fine strapped into their couches during that opening (though there might be some soiling of their spacesuits, but that is survivable).

It could be worse:

 

[Unstung]

It could be worse:

Speaking of ejection seats, ejecting from a lit Titan II seems like a pretty unpleasant experience.

 

[Artlav]

though there might be some soiling of their spacesuits, but that is survivable

I would suspect swearing instead. Lots of swearing and the CVR disabled for it.
But that is also survivable.

 

[RisingFury]

http://www.spacex.com/news/2015/05/06/crew-dragon-completes-pad-abort-test

SpaceX is claiming that:
"Had humans been on board today, they would have been in great shape."

 

[PhantomCruiser]

Comparing the tilt and whirl of the Dragon after trunk sep to an amusment park ride.

Have any of you seen the cage/fixture where people get strapped in and pulled back on bungee cords, then released? It's hard to tell on the video, but I've stood and watched the bunge-cage-of-death. The ride looks to be much more violent than the video, but like I said it's hard for me judge it; let's see what the crash test dummy has to say.

Even out of shape I can take 6G's (been there-done that), I was much younger then but it was only mildly unpleasant. On a proper acceleration couch it shouldn't be too bad at all.

 

[Evil_Onyx]

I think its impressive that they have done this.
But IMHO It took far too long to get a "safe" distance away, from what I can gather the capsule landed less then 1500m away and was sluggish off the pad. If a rocket was blowing up below it I don't think it would be capable of getting the crew to a relatively safe distance in time.

 

[C3PO]

Don't forget this is a 'last option' procedure. I'll take this as is over an ejection in a currently operational ejection seat any day, and may I add, by a huge margin.

 

[RisingFury]

The main point of safety is to make the rocket itself safe in failure. There's a reason you don't get a parachute on a plane...

Falcon 9 has one partial failure on record with one engine out. Not an ideal solution, but better than an explosion.

 

[statickid]

Interestingly, the announcer on the video says "dragon is tumbling as planned"

Since it is seemingly a very simple one axis spin the orientation of chairs could play a major role in safety, especially if the tumble is planned. Looking at again, I think it tumbled to deploy the chutes in the right direction

 

[RisingFury]

I'm sure they expected the tumbling. There are many engineers that worked on the capsule for years and spent more time designing it than a 5 minute look on Orbiter forum

 

[statickid]

Expected and planned are very different scenarios.

 

[Urwumpe]

It should rotate by about 180° to deploy the chutes, but after the first set of parachutes, the tumbling should get dampened before the big bang - but that didn't happen, the rotation rates even increased much more than after pilot deployment.

And that mostly, because the parachute risers got under tension approx. at the 90° phase of the oscillation - as I said, its a timing issue there, a few milliseconds later and the parachutes would not do much at all.

 

[MaverickSawyer]

It should rotate by about 180° to deploy the chutes, but after the first set of parachutes, the tumbling should get dampened before the big bang - but that didn't happen, the rotation rates even increased much more than after pilot deployment.

And that mostly, because the parachute risers got under tension approx. at the 90° phase of the oscillation - as I said, its a timing issue there, a few milliseconds later and the parachutes would not do much at all.

And that is precisely why they do these flights. Now they've got empirical data to use in revising the sequence of events.

 

[Urwumpe]

And that is precisely why they do these flights. Now they've got empirical data to use in revising the sequence of events.

And no objections to that. SpaceX says its fine that way, I say it needs some fine tuning.

 

[RGClark]

Perhaps they could attach deployable fins to the capsule like the trunk has.

Bob Clark

 

[Thunder Chicken]

Perhaps they could attach deployable fins to the capsule like the trunk has.

Bob Clark

Well, the capsule does need to reverse orientation, so fins won't necessarily help. The "tumble" is really necessary, but overshooting is not the end of the world. The drogue risers are long for this reason.

---------- Post added at 03:43 PM ---------- Previous post was at 02:44 PM ----------

I wonder if RCS could be used to stabilize the rotation? It would have to act quick, so it may not have enough force to null the rotation rate.

 

[RisingFury]

And no objections to that. SpaceX says its fine that way, I say it needs some fine tuning.

Based off of no hard evidence, a video and some hand-waving.

You'll forgive me if I take their word over yours

 

[N_Molson]

You'll forgive me if I take their word over yours

I would say that SpaceX is a much more partial source than Urwumpe. The difference is that they have a huge interest saying it worked perfectly.