A secret robotic space plane, a project of the U.S. Air Force Rapid Capabilities Office, is about to set its own space-endurance record. The project was planned for a nine-month-plus mission, and officials said they are close to that now.

The X-37B robotic space plane, also known as the Orbital Test Vehicle-2, was launched into Earth orbit atop an Atlas 5 rocket from Cape Canaveral, Fla., on March 5. Yesterday, it marked its 270th day of flight, considered in the past by project officials as the vehicle's upper limit for spaceflight.

"It's still up there," U.S. Air Force Maj. Tracy Bunko at the Pentagon.

Built by Boeing's Phantom Works, the X-37B spacecraft is about 29 feet (8.8 meters) long and 15 feet (4.5 meters) wide, with a payload bay about the size of a pickup truck bed. According to space officials, the X-37B resembles a miniature version of NASA's space shuttle and is powered by a deployable solar array power system.

The U.S. Air Force Rapid Capabilities Office is currently working on the X-37B Orbital Test Vehicle to demonstrate a reliable, reusable, unmanned space test platform for the United States Air Force.

Air Force Lt. Col. Tom McIntyre, the X-37 systems program director, said that X-37B controllers' initial plan was a 9-month mission but it may be extended "as circumstances allow." He explained that more flight time will mean additional experimentation opportunities and will allow permit its operators to extract the maximum value out of the mission.

The derivatives of the X-37B series have been proposed to possibly fly cargo and even crew to the International Space Station.

Arthur Grantz of Boeing Space and Intelligence Systems said the X-37B as designed now can be flown to the space station and supply cargo services by docking to the facility's common berthing mechanism, but a new design will able to carry up to seven astronauts into Earth orbit.