Monday, January 23, 2006

The Observer | World | Shuttle a deathtrap, says astronaut

Leave it to your most determined ideological enemies--in this case the Guardian of London--to point out your worst failings. In this piece, a retired US astronaut says that the Space Shuttle is the worst-designed, most dangerous craft that has ever taken to air or space. Yet people launch it anyway, thinking that they have no alternative--and astronauts won't throw away their chances at getting another flight.

I suppose everyone remembers where he or she was when Challenger blew up a little over a minute into launch because of a failed O-ring seal on a solid-rocket booster. Then, nearly three years ago, Columbia broke up and burned up on re-entry because of unsuspected damage to its wing on take-off. (What do you do when you're on a flight that, in effect, has already crashed?) The astronaut reminded us of another key failing: that the shuttle has no powered launch-escape system, like the one on the venerable Saturn C-5 (which was never required in all the Apollo years).

The Guardian piece is very short on the other things wrong with the Shuttle. But I can add a number of things to it, leading with its off-center (technically, off-axis) thrust on blast-off, because of the way the shuttle is mounted on the back of a fuel tank.

The irony of this whole thing--including the multibillion-dollar price tag that keeps mounting up for a fleet that is still grounded--is that the shuttle is really not all that great a launch system. It can put only 28 tons into low-earth orbit. To put that into perspective, the old Saturns could lob 110 tons into LEO--and if we still had the Saturn, we could have finished the International Space Station years ago.

Which is why, right now:

  1. Many teams of engineers, including some working for not-for-profit organizations, are coming up with workable proposals to use Shuttle-derived technology to build either
    1. a heavy-lift vehicle using a central core and a cluster of solid-rocket boosters, like an old Russian Energiya rocket, or
    2. a shuttle that makes sense--in which you mount the orbiter on a recoverable core that delivers its thrust on-axis, and don't use an external fuel tank with foam insulation that can tear a hole in your wing.
  2. A company called Sea Launch LLC is busy putting six-ton payloads into geostationary transfer orbits. (Once at the top of those orbits, these payloads fire their own engines to circularize and thus stay in geostationary orbit.) This is happening now. Today. And to my certain knowledge, Sea Launch is trying to get NASA's business to launch the remaining ISS modules. They launch at sea, from a converted oil-drilling platform, in an adaptation of the old Sea Dragon concept that the Air Force and Navy studied, but never did anything with.
  3. Another company called the Liftport Group is raising capital and building an infrastructure to build a new way to get into space: a carbon-nanotube ribbon that stretches from a point on the equator to a counterweight 100,000 kilometers up--high enough to launch a payload into an interplanetary orbit, as well as to place something in GEO. I have personally discussed with Liftport officials certain variations on the theme, that would permit an interplanetary launch in the plane of the ecliptic, using no rockets at all other than a reaction-control system ("steering jets") and eventually a much smaller engine for Earth return, if you're sending a crew.
So don't say that the space shuttle is the only game in town. It certainly doesn't have to be.

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