The X-33 could have produced that success, but for almost a year the space agency has kept the project out of the limelight. NASA officials characterize problems with the spacecraft as a temporary setback. Others in the space industry are skeptical. The X-33 was supposed to be a big improvement on the space shuttle. Cheaper launches would open the way for a range of commercial uses that are unprofitable today, from tourism to semiconductor manufacturing in space.
Critics say the craft's futuristic design is at the heart of the problem.
NASA could have chosen to build a space shuttle replacement by developing proven technologies, but instead chose the high-risk path of trying to build something almost entirely new. When NASA first asked for proposals to build a replacement for the space shuttle, three aerospace companies applied to work with the space agency on the project. Critics wonder how that could be. Even four years ago, they say, it was apparent that the technological hurdles facing Lockheed Martin's Buck Rogers design would be difficult to clear. The design required development of linear aerospike rocket engines, which have never been used in flight.