The second Boeing-built X-37B Orbital Test Vehicle, or OTV, left Cape Canaveral, Fla., at 2:46 p.m. PT, atop an Atlas V rocket, Boeing said.

"History was made in December when the X-37B became the United States' first unmanned vehicle to return from space and land on its own," Craig Cooning, vice president and general manager of Boeing Space and Intelligence…