Space Shuttle 2.0

[N_Molson]

But then we fall in politics again, I fear...

Another thing a Shuttle successor should solve is the matter of crew escape in the event of an early launch system catastrophic failure. Minishuttles can probably be pushed away by a solid booster pack. Do you know if the Dream Chaser is planned to have something like that ?

 

[Urwumpe]

But then we fall in politics again, I fear...

It was rather meant as rant about human psychology when spaceflight is involved. Unless Joe the Plumber can fly into space and touch space, he will not see it.

Do you know if the Dream Chaser is planned to have something like that ?

Sort of. It will use its de-orbit hybrid rocket engine for separating from the failing rocket, but it will not be comparable in acceleration to a proper LAS.

 

[Pipcard]

Dream Chaser will have a built-in launch escape system with hybrid propellant (same propellant for the orbital maneuvering engines).
edit: :ninja:

 

[BruceJohnJennerLawso]

The other interesting possibility with the Shuttle vast payload bay was the possiblity to catch back a massive satellite, repair and service it on Earth, then launch and deploy it again. But since most of the big satellites are beyond LEO, and often in GSO, this would have required a lot of dV and a (very) improved heatshield.

Welll, Im not quite so convinced of that. I suspect that actually landing a satellite, repairing it, then putting it back up might cost more than a new one, although the retrieval method would help with removing space junk.

But one of the original uses for the shuttle was the satellite retrieval mission in a military context, making a quick hop into orbit, grabbing a soviet recon satellite, then landing it to put it out of action during a crisis/all-out war. It was a cute little plan, but I find it hard to imagine it actually working. Maybe the bonus incentive would have been getting the chance to disassemble the hardware for information?

Or the planned orbital infrastructure beyond the STS based around Space Station Freedom, with the STS really only becoming LEO assembly platform and shuttle.

But such a vision is missing in spaceflight as whole today. When the highway system was build in the USA for a multiple of the ISS costs, nobody complained. When you try to do such a highway system in space, everybody will complain about "this money should be better spent on Earth" - even if this means that in the future missions will have to carry their own "highways" with them and cost a multiple of the "space highway" in total.

:lol: The Spacebahn, eh?

I guess thats one way of looking at it, but space infrastructure is harder to maintain, and its still hard to see how a Earth orbit station could have any value for space economics. I suspect that space will become very busy from about 2020-2070 or so, but its mostly going to be unmanned mining activities in the asteroid belt & elsewhere.

Still, its a good comparison. Infrastructure is ultimately the only way that space can be conquered, because its so hard to cancel. Even if the ISS has been expensive, and not quite as revolutionary research wise as was anticipated, (oh, the futurists always go overboard :facepalm the project is still going because its more wasteful to stop than to start. Can you actually imagine an Apollo/Constellation style program lasting for the entire lifetime of the ISS?

---------- Post added at 14:49 ---------- Previous post was at 14:46 ----------

Sort of. It will use its de-orbit hybrid rocket engine for separating from the failing rocket, but it will not be comparable in acceleration to a proper LAS.

Its still better than nothing I guess. The only problem with abort systems & space-planes is that the sudden acceleration during an abort places a ton of aerodynamic stress on the wingframe. Given that Challenger was destroyed by excessive dynamic pressure loads, one wonders whether an abort system would have made things worse on the space shuttle.

 

[Urwumpe]

Its still better than nothing I guess. The only problem with abort systems & space-planes is that the sudden acceleration during an abort places a ton of aerodynamic stress on the wingframe. Given that Challenger was destroyed by excessive dynamic pressure loads, one wonders whether an abort system would have made things worse on the space shuttle.

Accelerations don't cause aerodynamic stress.

Yes, you have to include the abort system in the dynamic pressure limits. The STS is close to the limit during Max-Q, so such an abort system would have been risky at least during Max-Q.

The sidemount configuration of the STS alone made most aborts risky anyway. You would need strong pusher systems(thrusters or push rods) for getting far enough away from the ET in a short time for not being sucked towards it again. The RCS is too weak when the tank is not almost empty.

Then you would need acceleration to leave the rest of the stack behind. Letting the SSMEs burn at emergency power for a few seconds would be sufficient for abort and possible with additional internal tanks, but such tanks would consume most of the payload bay volume then.

But then: No abort system would have helped Challenger. The destruction came without apparent warning. A simple copper wire in the ET facing section of the SRB would have been enough to sense a dangerous joint failure. (if wire molten away, hot exhaust gases are leaking). But such a sensor was not even fitted to the STS after Challenger.

 

[BruceJohnJennerLawso]

Accelerations don't cause aerodynamic stress.

Yes, high velocity and static pressure make for increased dynamic pressure. That was one of the issues with the Shuttle payload wise; It had to spend more time fighting gravity drag since the Orbiters wings could only handle a certain amount of dynamic pressure caused by turning towards the horizontal faster. (better in order to gain orbital velocity faster) This was supposed to have cut a noticeable chunk into the payload lifting ability of the shuttle, at least according to one source Ive read.

The sidemount configuration of the STS alone made most aborts risky anyway. You would need strong pusher systems(thrusters or push rods) for getting far enough away from the ET in a short time for not being sucked towards it again. The RCS is too weak when the tank is not almost empty.

Why would the ET suck it back in?

 

[Urwumpe]

Why would the ET suck it back in?

Bernoullis principle, that total pressure (static + dynamic pressure) is constant for the same incompressible flow system. Also applies with some modifications to supersonic speeds (when flow is relatively incompressible again).

Is the same phenomena that can make ships collide in a channel, when passing by. between them the pressure is lower and they are sucked together, unless you steer against the force.

You need to get some separation between the vessels ASAP, or you will have a hard time fighting the huge forces that want to bring you back to the tank.

Such a collision also destroyed a SR-71 once, when a drone separated at high speed did not get enough separation and returned. Or you also get them when you drop bombs at high airspeeds, you need to eject the bombs with enough speed or they will not leave the bomb bay.

 

[tblaxland]

Off-topic posts moved to new thread: Ejecting bombs from bomb bay