The idea for a spaceplane has been around for 40 years. The National Aerospace Plane program, created to design a supersonic jet that could fly payloads into space like the shuttle and also be used as a bomber to reach destinations around the world in a couple of hours, was scrapped in 1994. Engineers realized that the plane would never be able to reach orbital velocity on its own. More recently, NASA abandoned hope for the X-33, a proposed replacement for the space shuttle that was supposed to fly from the ground to orbit in a single stage, rather than using a booster rocket, because the technology never quite panned out. Now, NASA has earmarked $4.8 billion for a Space Launch Initiative to develop a replacement for the shuttle that will be another two-stage reusable launch vehicle but cost much less to maintain and operate. The Defense Department has piggybacked on that program. The first demonstration of the Pentagon's version of this spaceplane is expected to occur around the end of the decade, and by 2014 the military hopes to have an operational, unmanned vehicle.
That spaceplane, known as the Space Operations Vehicle (SOV), will be a cargo carrier that can lift a variety of payloads and probably won't be any bigger than the space shuttle. In a separate program, the Pentagon is designing a smaller unmanned spaceplane, called the Space Maneuver Vehicle (SMV), that could be launched by the SOV, a rocket, or even a high-flying airplane. The SMV could remain in orbit for up to a year before landing autonomously on a runway. Boeing has already built a scale version and dropped it from a helicopter to demonstrate its landing capability. Among the payloads the SMV might carry is the Common Aero Vehicle, a reentry craft intended to deliver weapons from space (see "Bombs Away").
Missile defense is the single largest R&D category in the Defense Department's budget. The Bush administration has requested more than $7 billion in fiscal 2003 to build a system capable of shooting down ballistic missiles. But before that occurs, the Pentagon will have to design better infrared satellites than the nation's existing Defense Support Program (DSP) birds. Existing DSP satellites can tell whether a missile has been fired at the United States, but intercepting it requires being able to distinguish between warheads and decoys, track multiple objects released by a single booster, and hand off trajectory information to an interceptor vehicle-none of which DSP can do.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.