One of the longest-running sagas in the space age has been the quest for a practical, reuseable space plane. The space shuttle program’s winding down now, but it’s not as though it’s ever been the only game in town. Before it came along, there were multiple efforts to design a space plane (within NASA, in the military community, and of course in the then-U.S.S.R.). For most of the shuttle’s operational life, efforts within the U.S. to build anything similar were essentially shut down — but as the shuttle’s reliability issues became more apparent, and the end of its working life neared, interest started flaring up again.
For the U.S. Air Force, this took the form of the X-40 testbed, while NASA didn’t want to be left out and so started its own X-37 program — both unmanned, both started in 1996. But the programs’ political fortunes came and went with the usual political tides — in 2000, the Air Force’s X-40A craft was transferred to NASA for their use in testing X-37 technology. Then in 2004, NASA got tired of the now-combined program and gave it all back to the military, and it’s been a DARPA research project ever since.
Probably the best video to be released from either of the programs comes courtesy of the Smithsonian Institution’s Air & Space magazine — it shows a 2001 drop test of the X-40A (back when NASA was running the show):
Since the program got handed back to the military, it seems to be moving along well. The January issue of Air & Space has an in-depth article on recent developments in the X-37 program, scheduled now for its first launch this summer on an Atlas V rocket. There’s also a good writeup on the history of the oddly intertwined X-37 and X-40 programs at a site called the Directory of U.S. Military Rockets and Missiles.