A United Launch Alliance Atlas V rocket carrying the Air Force's X-37B… (Pat Corkery / United Launch…)
An experimental robotic space plane was launched into orbit atop a massive Atlas V rocket Saturday for a classified Air Force mission that could last up to nine months.
The 19-story Atlas V and the space plane, dubbed the X-37B Orbital Test Vehicle, blasted off from Cape Canaveral in Florida at 5:46 p.m. Eastern time.
The unmanned X-37B, which resembles a miniature space shuttle, is about 29 feet long with a wingspan of about 15 feet. The spacecraft draws solar power for energy using unfolding panels.
While the Air Force has said the space plane is designed to stay in orbit for 270 days, it hasn't said much about the overall mission. It has said only that the vehicle provides a way to test new technologies in outer space, such as satellite sensors and other components.
The Air Force had initially planned on launching the X-37B on Friday, but didn't because of poor weather.
Saturday's launch marked the second time that the Air Force has put an X-37B into orbit. The first was launched from Cape Canaveral last April, and 224 days later, it made a fully automated landing on a 15,000-foot-long airstrip at Vandenberg Air Force Base, northwest of Santa Barbara.
The X-37B vehicles were built by Boeing Co. in Huntington Beach. Engineering work was done at the company's facilities in Huntington Beach and Seal Beach. Components also came from Boeing's satellite-making plant in El Segundo.