This is a very difficult problem they're trying to solve. they're trying to develop a vehicle that can travel at immense speeds through the upper atmosphere with high forces and very high heat, and to be able to control that vehicle so that it can hit an intended target thousands of miles away. the purpose -- >> jon: we're looking at the launch of the missile that then releases this thing, and it basically glides back to earth with a rocket assist at, what, one # thousand miles an hour? >> yes. that's right. the rocket gives it the initial boost, and then it comes back down and glides through ...