NASA's Shuttle Plans 549
Gerhardius noted a NYT article (you know the obnoxious deal) about new "shuttle" designs coming out of NASA. The payloads are riding up top to avoid debris.
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NASA's Shuttle Plans
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Whatever happened to single-stage-to-orbit? (Score:5, Interesting)
As long as we're no longer trying to send up cargo along with personnel, now might be a good time to revisit single-stage-to-orbit designs such as the Delta Clipper [wikipedia.org] and the Roton [wikipedia.org].
I don't recall any debris problems with either of these designs, although the leg design seriously needs to be rethought. If you have four legs, a failure of any leg results in disaster (witness the spectacular failure of the Delta Clipper). Six legs, on the other hand, would be far more stable...you could lose any three (provided they're not all adjacent) and still pull off a successful landing.
Overly fragile? (Score:3, Interesting)
I understand that there are some sizable forces acting on the launch vehicle, but how can insulating foam do so much damage?
And, if insulating foam can damage the tiles, what about micro meteors or drifting debris from previous flights?
Isn't there a way to put a shrouding over the tiles that would be jettisoned with the fuel tank? Protect the tiles until the shuttle is free of the fuel tank and solid rocket motors.
Too Simple, Really (Score:4, Interesting)
"A ship in a harbor is safe. But this is not what ships are built for."
I would be fine with the new design concepts if we use a Crew Return Vehicle design. One, it can carry more people and a small amount of cargo. Two, it can also be placed atop like an Apollo-style capsule. Three, it is more reusable. Think of it as a mini-Orbiter.
Reusing and readapting the ET/SRB devices is a frugal idea as well. We just need something to routine get up and back to the ISS. Perhaps we should also look into making an in-orbit shuttle that stays in space and can move between LEO, the ISS, and the moon.
Delta Clipper (Score:5, Interesting)
It was originally an Air Force project. When video of the first test was shown at ConFrancisco in 1993, it was said that if it ever got transferred to NASA they'd kill it.
NASA was threatened by the Delta Clipper. A ground crew of 3 instead of 15,000? We can't have that! A NASA employee failed to connect the landing gear hydraulic line for one of the tests shortly after NASA took over the project.
These days NASA is more of a jobs program than a space program.
Re:Delta Clipper (Score:3, Interesting)
This is true of any Federal job, and most state government jobs as well. Any large commercial organization will also have this problem. It's not a NASA thing, it's an organizational thing.
I saw the case of a NASA employee sexually harass a student he was mentoring. He was told he couldn't mentor anyone else, but he wasn't fired.
Re:engineering scapegoats (Score:3, Interesting)
Yes, the Shuttle is a complex machine. I've heard that over and over again each time I see a shuttle launch program on TV, or when astronauts talk about it.
That is precisely the problem... not the ice damage or the configuration. Any engineer from any discipline can tell you that each time you add a new part or increase the complexity of a machine that you are likely to screw it up.
At their heart, a rocket is a very simple machine. You throw "stuff" out the back end of the rocket, and as fast as you possibly can. The trick that modern rocket builders need to deal with is that to achieve orbital velocities you need to have a rocket that sends "stuff" out so quickly that it reaches insane temperatures, and even incredible temperature differences (going from -200C to 4000C in less than 10 seconds for the fuel). You also need to have a "fuel pump" that can effectively pour a controlled but huge volume of fuel at constant (or at least consistant) pressure. Indeed, it is the design of an efficient turbo pump to push fuel into the combustion chamber that most rocket scientists spend their time. And where most of the complexity comes in. Dealing with cryogenic fuels also has some additional problems (in the case of the shuttle).
The trick to reduce errors and failures is that you have to simplify the idea and approach. One solution to this issue is that if you have an assembly line of rockets being built, you have other incentives to simplify... mainly because it gets cheaper to build them in the first place when there are fewer complex parts.
The current fleet of Space Shuttles are each hand-crafted and in many ways unique craft each in their own right. They each have a very interesting history, and in some areas you can't "mix" and "match" or change parts (although sometimes NASA tries real hard in this prespect).
As you also pointed out, there were problems with the tile system. When it was first proposed, even before STS-1 with Columbia, there were quite a few complaints about this heat-protection system. There was at the time a "wait and see" standard mantra coming from NASA, to see just how effective it was. And indeed it has been quite successful in a number of ways, but it has proven to be far too fragile for repeated flights.
The other thing that a redesigned Shuttle would have in its favor is that it wouldn't have the U.S. Air Force RFP requirements, many of which caused huge problems and setbacks for the Shuttle program even before it got going.