The US plans a special test in June during which a ceramic test unit will be mounted on a Mk-12A re-entry vehicle (without the nuclear warhead), launched into space, and then dropped back into the atmosphere. The point of the test is the develop new ultra-high temperature materials that could be used for future spacecraft. The current space shuttle has relatively inefficient wings because the leading edges must be blunt and thick. If the new material works, leading edges on future spacecraft aerofoil surfaces could be relatively sharp and much more efficient. --Stephen V Cole