Right thesis, wrong facts
Posted by aogTuesday, 04 February 2003 at 21:56
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quotes Greg Easterbrook
on the Shuttle. Rand Simberg hits the high points
of the problems in a more recent article
, so I'll just respond to the points in the cited quote.
I agree with Mr. Easterbrook's main thesis but he overstates his case. His iteration of physical conditions is highly misleading. Although Rand Simberg has already taken his shot, allow me to attach Easterbrook's claims that you quoted.
- Rockets were built as throw away not because "the forces of space flight twist and sizzle machines into scrap" but because recovery is very hard and expensive. I fly model rockets myself and the recovery systems are far harder than any other part of building and flying. And one notes that in all the flights the SSME's haven't had problems (and in fact the trickiest bit of technology is those is the cryogenic pump which doesn't even notice that it's flying). So Easterbrook's claim that the engine "is impractical to use again even if you can get it back" is clearly false on its face.
- The comment that "During ascent, the shuttle must withstand 3 Gs of stress" is laughable. I've got rockets made out of paper and balsa that can handle 10 G's of stress. I've got another model made of somewhat stronger stuff that handle FIFTY (50) G's on takeoff.
- As for temperature, it's true that re-entry is tough (notice - the problem is in the recovery of the rocket). However, as we discussed earlier concerning solar power satellites, in Earth orbit the equilibrium temperature from solar radiation is about 270K or roughly the freezing point of water.
- Finally, the dead stick landing is a bit sticky, but modern avionics should find that not too difficult. There are other designs that provide powered landings. But Easterbrook is closer here than elsewhere because recovery is in fact a hard problem.
Easterbrook's main point, that the Shuttle has been overhyped, under performing and over budget from day one is dead on. I've heard the $500 million per flight, although some claim it's closer to $800 million. But the point of my tirade is that this that NASA hasn't failed because of the inherent difficulties but for other reasons.