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SpaceX wins $440M contract with NASA to develop Space Shuttle successor

spaceflightnow.com

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Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#61

Post by slurgfest »

codex wrote: post #14
dfriedmn wrote: post #7

Earlier quoted context omitted.

One of Musk's original goals was to do it 10x cheaper, and accd to his recent discussion with NPR, he's already at 1/8th of the cost(1). What an amazing accomplishment. 1. http://www.npr.org/2012/05/18/153015277/on-eve-of-launch-spa...

This speaks more to the colossal clusterfuck that was the overengineered, unreliable Space Shuttle program. Doing it 10x cheaper than the Russians would be a real accomplishment.

Doing it exactly as cheaply as the Russians would be a real accomplishment. Because it would allow us not to be forced to use the Russians for everything!

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#62

Post by jlgreco »

droithomme wrote: post #47
jlgreco wrote: post #36

Earlier quoted context omitted.

Well, they said the Titanic would be un sinkable, not less sinkable than previously developed ships.

Actually White Star claimed it was "designed to be unsinkable", not that it was. And this was after describing a long list of safety features. It's a very dangerous attitude, to claim a priori that your design is safer. The Titanic was so safe that it was not necessary to carry enough life boats for all the passengers. That's how safe it was. Once your focus is on the incredible confidence you have in the safety of y…

The difference in this situation of course is that SpaceX is claiming that their rocket will be safe because they are adding more lifeboats (in other words, they are bragging about their planned abort systems).

They are not claiming to be designing a rocket that cannot fail, but rather one that fails safe (though low failure rate is undoubtedly a high priority for them.)

I do not see how such an attitude could possibly be a liability. What is preferable?

Edit: I'm trying to understand your point of view. Is your issue that the are trying to make it the safest, or that they said that they are trying to make it the safest?

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#63

Post by btilly »

JoeCortopassi wrote: post #21

Every time I see something like a rocket or space shuttle launch, I can't help but wonder how much of the weight and cost could be saved using alternative methods . Even helium/hydrogen filled balloons could get them a good chunk of the way there. I know that would be horribly impractical for something the size of the shuttle and it's rocket boosters/fuel tanks, but if a balloon rig can get them to 120,000 ft they ha…

There are companies trying to do that as well. For instance http://en.wikipedia.org/wiki/Orbital_airship describes one where an airship that is part blimp, part fixed wing follows a trajectory where first it is lifted by being lighter than air, then it gets lift from moving fast through thin air, then it gets lift from being near orbital velocity.

Theoretically they should be able to get things in orbit very cheaply compared to rockets. So far those technologies have not worked in practice.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#65

Post by FrojoS »

btilly wrote: post #59
rbanffy wrote: post #54

Earlier quoted context omitted.

> It is easy to use superlatives like "safest rocket ever designed" Well... Considering its predecessor, the shuttle, was one of the least safe rockets ever designed, it's not very hard to improve upon. Use multiple engines, avoid solid rockets (at least the ones that cannot be throttled down), mount your heatshield where nothing crashes on it, keep it simple...

Considering its predecessor, the shuttle, was one of the least safe rockets ever designed... According to http://www.futurepundit.com/archives/000940.html as of 2003, the space shuttle had the best safety record of any rocket design that had been flown to space at least 100x. That fact would argue strongly against your claim.

Sure, for a billion per flight you can more than double check even the most abstruse piece of that nightmare construction. Wings for instance, which we all know are super important for a spacecraft.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#66

Post by gvb »

btilly wrote: post #20

It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. I will be the first to applaud if SpaceX achieves this goal. I am certain that they want to achieve this goal. Bu…

From TFA, SpaceX will demonstrate the launch escape system both static on the launch pad and at max dynamic pressure (worst case in-flight).

It looks like the Apollo system had good abort coverage. http://en.wikipedia.org/wiki/Apollo_abort_modes

The shuttle could not pass the tests that SpaceX will demonstrate. Post-Challenger, it was substantially improved, but still had survivability gaps and questions whether the some of the abort modes were truly survivable (especially under the more severe conditions). http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Post-...

The best the astronauts could do on the launch pad was a "zip line" escape http://americandigest.org/mt-archives/american_studies/how_t... (with scary pictures: http://www.collectspace.com/ubb/Forum30/HTML/001111.html).

While the SRBs were burning, the shuttle could not abort at all. This is the ascent period when the Challenger was lost.

After the SRBs detached, there were several options to abort, all of them assuming the shuttle was mostly functional. For the first four shuttle launches, the shuttle had ejection seats so the astronauts (two, anyway :-O) could escape a crippled shuttle. http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#70

Post by alpine »

jonmrodriguez wrote: post #32
JoeCortopassi wrote: post #21

Every time I see something like a rocket or space shuttle launch, I can't help but wonder how much of the weight and cost could be saved using alternative methods . Even helium/hydrogen filled balloons could get them a good chunk of the way there. I know that would be horribly impractical for something the size of the shuttle and it's rocket boosters/fuel tanks, but if a balloon rig can get them to 120,000 ft they ha…

Getting upward isn't the problem. It's acquiring the massive horizontal speed required to orbit that is more energy expensive. http://en.wikipedia.org/wiki/Delta-v_budget#Launch.2Flanding

The higher you are, the greater your tangential velocity to the ground. Launching a rocket from the top of Mount Everest vs a beach on the Dead Sea is cheaper in terms of energy required to attain a given altitude.
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