The Air Force launched its unmanned mini-shuttle late Wednesday morning. An Atlas V rocket lifted it up and out over the Atlantic.
This is the fourth flight for the military research program, which is shrouded in secrecy. The last X-37B mission lasted 674 days and ended with a California touchdown.
Altogether, the first three X-37B flights spanned 1,367 days. That’s 3½ years.
The Air Force won’t say how long this particular mission will last or where it will end. Public commentary about the launch ended barely five minutes after liftoff, well before the space plane was supposed to settle into a relatively low orbit.
The X-37B looks like a miniature version of a NASA space shuttle. It is 29 feet long — about one-quarter the length of a space shuttle — and its wingspan is about 15 feet.
Like the old shuttle, the Boeing-built X-37B launches vertically and lands horizontally, is reusable, and has lots of room for experiments. But no one flies on them; they are operated robotically.