Those crazy genius at SpaceX have a new plan: fully reusable rockets. Their system is surprisingly simple, but they don’t know if it will work. But CEO Elon Musk says they are going to try it. Here’s the low down.
After stage separation, they want to turn the stages around, relight the engines, aerodynamically steer them back to the launch pad and make them touch down smoothly on landing legs.
That sounds good. My only question is: where the hell are they going to get all the fuel for that powerful landing retro-propulsion? Are they going to increase the size of their spaceships.
I’m certainly not a rocket scientist, but wouldn’t it be more simple and smarter to use the same thermal-shield turn-around system and parachutes and huge airbags to achieve the same smooth landing effect of the retro propulsion? Perhaps it won’t be as cool as the robotic landing legs, but I’m sure it would be lighter and safer — just imagine that stage dropping down with a failed engine, a much higher probability than a failed parachute.
[SpaceX]
kyle
Saturday, October 1, 2011 at 10:47 AMerm, the fuel will come from the first stage fuel tank (and in the case of the second stage, the second stage tanks)
and drag will do the rest
hooray science!
kyle
Saturday, October 1, 2011 at 10:47 AMAddendum: because parachutes don’t work on mars
David S.
Saturday, October 1, 2011 at 11:22 AMI can save them a lot of money and time – this won’t work.
The fuel they don’t burn on ascent that’s needed to land each stage (and the heat shields for each stage) still has to be lifted, it becomes dead mass, payload in itself, and there’s no way they can carry enough fuel they do burn to put all this dead mass, plus their real payloads, into orbit. The required mass-ratio would be way beyond anything the F-9 (or any other known rocket design) can muster.
They _might_ be able to recover the first stage with parachutes and airbag flotation (this was the original F-1/F-9 plan), but the second stage, which reaches orbit and would need heat shielding and retros as well? Not likely. This “everything comes down gently on plumes of flame” plan is even more expensive and impossible than even a basic second-stage recovery with chutes in the ocean.
Aravind Reddy Kaithy
Saturday, October 1, 2011 at 12:53 PMThey should use some kind of wings to glide during land.
so impact will be lesser and no fuel require to compensate gravity on descending, This is long time dream for NASA.
I Wish them success.
The Joker
Saturday, October 1, 2011 at 2:48 PMSurely a concept like Virgin have employed would make more sense, then all you need is enough fuel for initial orbital breaking rather than powered decent. I should imagine that this concept could then be called “hybrid” and all the tree huggers would give it the thumbs up.
EckyThump
Saturday, October 1, 2011 at 3:03 PMYeah, gotta say the Virgin concept makes the most sense to me,… Landing the way they show in the vid, has been tried before, but even though they succeeded a couple of times, it proved too much of a dick around! If they are gonna stick with a rocket, which will be much cheaper, they should just do what they did with the Shuttle’s main tank! #]
Stuart
Saturday, October 1, 2011 at 4:05 PMGotta say I agree with the author. This looks very improbable. Parachutes and airbags are going to be a whole lot lighter. And did anyone notice that there is a big manoeuvre missing in the animation – the second stage goes in heat shield first and then somewhere, in the atmosphere (and missing in the clip), manages to spin itself and land tail first. Good luck doing that with little attitude thrusters and no aerodynamic control surfaces.
Stuart
Saturday, October 1, 2011 at 4:09 PMLets stop dicking around with these little fireflies and just build a friggin’ space elevator.
Edward
Saturday, October 1, 2011 at 7:16 PMCheck out all the rocket scientists on this page criticizing SpaceX.
shannon Rios
Tuesday, October 4, 2011 at 10:21 AM+1
Steve
Tuesday, October 4, 2011 at 2:29 PMits not rocket surgery!
jeremy
Wednesday, October 5, 2011 at 5:19 PMnot convinced chutes would be lighter actually. delta clipper did the math on this and is looked feasable under certain assumptions, so this is possible too. As one writer said, drag actually kills most of the delta-v passively, the retros just need to reverse terminal velocity with the legs extended. The key is restartable engines with the right throttlable specific impulse and awesome computer control, much more doable now. This is basically what the new mars rover is doing in its terminal phase, and the reentry drag on mars is much less of a help. The safety discussion is fair though – if your engines fail to restart you are well rooted :-)