Trent Shipley <[EMAIL PROTECTED]> asked
Why couldn't you build a lauch vehicle with a fan-jet 1st stage
(recoverable), Ram or scram jet 2nd stage (stage and recovery both
optional) and a rocket 2nd or 3rd stage (disposible)?
Yes, you could. Indeed, the Pegasus launch system uses just this,
without the second stage: a rocket carried to an altitude by a jet.
(The higher altitude means that the rocket engine's exhaust size can
be set for low air pressure/vacuum. Rockets launched from the earth's
surface must have exhaust bells sized to the higher surface press.
This makes for a size that is less efficient at higher altitudes. The
airplane launch means the rocket can be positioned in just the right
place and direction.)
The problem with a multi-stage launch is that it remains expensive. A
far-sighted goal is to bring down the cost to no more than 100 or so
times that of flying overseas first class -- among other things such
as quick turn around, instead of three sets of equipment to fuel,
service, and pilot, a combined cycle engine needs only one vehicle.
(I would like to see even lower costs.... :)
--
Robert J. Chassell Rattlesnake Enterprises
http://www.rattlesnake.com GnuPG Key ID: 004B4AC8
http://www.teak.cc [EMAIL PROTECTED]
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