Slashdot Mirror
Robot Spaceplane To Launch In 2008
FleaPlus writes "The US Air Force has announced that it is developing an unmanned reusable spaceplane, the X-37B Orbital Test Vehicle. The first launch is in 2008 on an Atlas V rocket. The X-37B will be one-fourth the size of the Space Shuttle and serve as a testbed for technologies for future reusable spacecraft. Its predecessor, the X-37, was drop-tested from the Scaled Composites White Knight mothership earlier this year."
On the other hand, we don't know what to call it other than "Buran" because the Soviet Space Transportation System (SSTS?) was never given a proper name other than letting people call it Buran.
By the way, does anyone know what kind of reentry vehicle -- lifting body, straight wing, delta wing -- this thing is?
The Russian and U.S. "capsules" were blunt body reentry vehicles -- some were ballistic, others used an offset CG for a small amount of hypersonic lift to mitigate the G-load and thermal load of reentry. Apollo along with the Russian Zond used offset CG to good effect for reentry from lunar distance. All landed mainly by parachute with either crushable couch struts to mitigate a land impact (Apollo, if they had to go down on land) or braking rockets -- the Russians may have crumped a Soyuz with a landing rocket failure, resulting in broken teeth.
The Shuttle famously uses a delta wing that produces a large amount of lift everywhere from hypersonic reentry down to the subsonic landing speed, and this famously drove up the cost and weight. Max Faget had a straight-wing Shuttle proposal that was equally famously rejected, both on the idea that straight-wing craft have nasty hypersonic handling (think Yeager and his tumble in the X1A, his tumble in the NF104, and Mike Adam's accident in the X15) along with the Air Force wanting the Shuttle to have more hypersonic cross range. But Faget's explanation of the thing is that the straight wing vehicle pancaked in -- it didn't really fly on those wings in hypersonic reentry -- and the straight wing Shuttle was like a cookie cutter applied to an Apollo heat shield, and the control of blunt body reentry with offset CG for some small amount of lift was well tested. But the Faget Shuttle would have to do some kind of Alley Oop maneuver at subsonic speed to transition from a full stall pancake attitude to proper flight on those straight wings, and there was some concern about doing that stall recovery safely.
Then there was the DC-X, the closest thing to a Buck Rogers spaceship from the 1930's comic books, which was to reenter as a blunt body (don't remember if it was nose first or tail first) but land on its tail using rocket thrust. Of course the DC-X on landing is this big mainly empty fuel tank so it is not going that fast before the rockets cut in for landing, but if the rockets fail, you are going to crump that thing.
Perhaps the only new thing under the sun for reentry (although not an orbital reentry) was the Rutans' "shuttle cock" folding tail where they reentered with a stable, high drag configuration and then straightened the tail for atmospheric flight and landing.
NASA wants to go back to the Apollo style reentry and landing but probably on land using parachutes and landing rockets like Soyuz and the Chinese spacecraft. You save big time on weight and there are safety advantages in terms of heat tile damage, but this low-control landing has problems of its own. Do you suppose NASA could wait awhile on the outcome of this Air Force project to see how it turns out?
Do you understand anything about orbital mechanics? Orbiting spacecraft cannot "loiter" except in a very few, very special kinds of orbits. The cannot meaningfully "reposition" with the specific impulse limitations of the engines and fuel available today. Oh, the heck with it: for all intents and purposes they cannot meaningfully do ANY of the things your message suggests.