"Tom Kalvelage" wrote in message
om...
For simplicity, both stages are VTVL. The only thing close to new
engineering is jettisoning or retracting the second stage exhaust
bells and closing the holes in the heatshield for reentry, then
opening the holes for the engines to fire through on landing.

It's been suggested that instead of doing anything fancy like that, you
could just run some LH2 through the engines during re-entry, or even run the
engines at "idle" during re-entry. Either of these would greatly reduce the
heat load on the engines.

The DC-X, Armadillo Aerospace, and the Japanese RVT vehicle have
demonstrated VTVL. The Shuttle has holes in it's heatshield that it
closes and opens (landing gear).

True, but you've got to be very careful about this. Failure of any of the
doors to close would result in loss of vehicle if re-entry is attempted.
Furthermore, failure of the doors to open (on landing gear and/or braking
rockets) would also result in a crash upon landing.

Apollo had heatshields. Soyuz does
a good job on reentry. There are lots of engines available. If the
stages were only built for 10-20 reuses, we could keep fielding
improved versions, learning about SSTO and BDB in the process. It
would likely help the US launch industry regain market share. Many
rocket scientists have proposed some or all of this before.

So why is there no interest? Is the concept goofed up in some
non-obvious way? Am I missing something?

There certainly is interest (as evidenced by start-ups which are pursuing
similar designs), but NASA is another story. If they go ahead with plans to
return to the moon, that leaves little money to develop new launch vehicles
like you're talking about. They'll be spending the money on the CEV and on
the missions this modular spacecraft flies.

Jeff
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