PDA

View Full Version : A launch abort system accelerates HOW fast?!?



Dr Mordrid
16th November 2012, 16:15
Speaking of how fast the SpaceX Dragon's SuperDraco launch abort thrusters can accelerate it, this from today's Royal Aeronautical Society lecture:

"Duncan Law-Green @Rocketeer_UK

SuperDracos 6-8gs, will boost through sound barrier in 4s"

And I thought 0-100mph in a few seconds was a rush :p

degrub
16th November 2012, 19:32
Well, at those sudden g's they'll black out. If they wake up then they survived. If not, then too late anyway.

cjolley
17th November 2012, 05:58
If you are trying to get away from a gigantic explosion fast=good :D

Dr Mordrid
17th November 2012, 09:26
Technically, when most rockets break up it's an intentional conflagration and not an "explosion." The Fligh Termination System detects a fatal fault (enginr failure etc.) and sets off small linear shaped charges that open the tanks, disperse and ignite the fuel/oxidizer so it doesn't hit the ground in bulk. Falcon 9's advantage is that ot can survive most of these faults and continue flying, even self-correcting its course.

The rockets that can literally explode are solids like the solid boosters used on the Shuttle, Delta and Atlas V. A while back a Delta II had such a failure just after launch that sprayed flaming solid fuel all over the pad and the surrounding area. Messy.

Challenger was a mix; the solid sprang a flame plume due to a seal failure on the tank side, which set off the main liquid tank. If the flame plume had pointed most anywhere else Challenger would have survived as the solids were nearing cutoff and jettison at that point.

cjolley
17th November 2012, 15:24
The rockets that can literally explode are solids ...

Except when they aren't (http://www.youtube.com/watch?v=dqT90VmYgEU&feature=related) :(

Dr Mordrid
17th November 2012, 19:15
VERY few liquid boosters catastrophically fail on the ground like that now, and that was an old Russian film. Looks like the N1-5L pad explosion.