The Orion spacecraft and Space Launch System rocket have been attached at the hip for the better part of two decades. The big ...

NASA's experimental X-43A didn't have a pilot and couldn't fly independently, but its blisteringly high speeds showed that hypersonic flight was possible.

-Air-launched from a B-52, the X-15 reached a record-breaking speed of Mach 6.7 and flew high enough to earn astronaut wings for eight of its pilots. -While never intended as a weapon, the X-15 was a ...