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To: chimera
I'm not sure an all-weather launch vehicle with 100% guaranteed safety is in the cards, for NASA or private industry.

I think the problem is with the rocket paradigm that dates to Vaun Braun in the 30's. Lifting things vertically with thrust alone and carrying 100% of your oxidizer is just dumb.

Aircraft based launchers I think are the way to go. They can lift far more weight using less thrust than pure rockets, and can have a "first stage" that's air breathing thus don't carry as much oxidizer. You can also do things like air-refueling, where you tank up a vehicle in flight with far more weight than it could safely heft off the ground. I think the SR-71 cannot take off with a full load of fuel and it hits a tanker as a matter of course.

One of the good proposals I've seen is a Vulcan Bomber looking vehicle with turbojets and a rocket engine in the tail. It launches with jets, hits a tanker for extra kerosene, then uses the rocket to fly to about 300k feet and Mach 10-12, where it dumps out an upper stage that could be a crew module or cargo stage. It could literally fly every day.

There were designs on the books in the 70's for turbojet/ram/scram/rocket vehicles. Yes, there is a heating problem. But we re-enter the shuttle from Mach 25 with no problem, as long as you don't smack it with FOD on liftoff. A vehicle with Shuttle re-entry ability, and using atmospheric oxidizer to about Mach 12 I'd think would be plenty doable.

The only problem is that it would kill the NASA pork barrel, and the technology would become public domain and other countries would purchase the technology eliminating the small "manned orbit" club we now lead. National security of allowing such a vehicle to be sold at will is a problem too. But I think we should take that risk and built it.

By the way, I haven't stopped laughing at the "space elevator" promoted by some. Yes, it could be built, but I think the potential failure modes are far worse than any flying vehicle. It's guaranteed to be hit by space junk, as literally EVERY hulk in space that's not maintained in Geosync WILL hit it eventually. There are some big hunks of junk up there, and you can't move the thing to avoid them.

71 posted on 09/28/2005 10:36:26 AM PDT by narby
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To: narby
Airborne launch systems always involved some tare weight. With manned systems, you're always going to have some of that. The shuttle is expensive because the tare weight is high and we haven't been able to meet the original timetable for vehicle turnaround. Perhaps those initial estimates were overly optimistic, I don't know. But, whatever, the reality is that we have at this time only one mode of getting into space. Developing another is fine and is probably the way to go, but I'd hate to see another long-term "gap" in the program, or, perhaps worse, having to hitch a ride with others to get up there.

Look, people, we need to understand that our space program is still an R&D effort. We're going to have mistakes, restarts, delays, and the like. Those things happen when you're in a development stage. I don't like them anymore than you do but I have been in the research game long enough to know that they're going to happen. The key point is not to throw away the whole smash because of setbacks here and there. If we're serious about long-term exploration and colonization beyond this planet, we need to keep that vision in mind, and not let it be obscured by penny-ante politics and small-minded thinking.

75 posted on 09/28/2005 10:47:17 AM PDT by chimera
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