Similar to the Space Shuttle in appearance, the diminutive X-37B is about a quarter the size of the old shuttles. But there are major differences. Lacking a crew, the spacecraft has no cockpit windows. The X-37B has a payload bay about the size of a pickup truck bed.
The Air Force’s secret space plane has been up in orbit for nearly 500 days—a space endurance record. But nearly a year and a half into the mission, the Pentagon still won’t say what the X-37B is doing up there, or when it might come back.
The U.S. Air Force boosted the robotic X-37B atop the nose of an Atlas-5 rocket in December 2012. Since then it’s orbited the Earth thousands of times, overflying such interesting places as North Korea and Iran.
And while the original Space Shuttle could stay in orbit for up to 17 days—a limitation largely due to the needs of the crew—the first X-37B mission, OTV-1, spent 225 days in space under the guidance of Air Force space flight controllers at Schriever Air Force Base, Colorado. The second mission, OTV-2, handily doubled that number, clocking 469 days in orbit. OTV-3 is currently at 482 days and counting.
Eventually—nobody knows when—the pudgy space plane will glide back down to Earth like the Space Shuttle it resembles, rolling to a stop on an Air Force runway in California.
The X-37B began as a NASA project to build a small, unmanned space plane. NASA handed the project over to the Defense Advanced Research Projects Agency in 2004, but after budgetary problems the program was transferred to the U.S. Air Force Rapid Capabilities Office, which continues to manage the X-37B program. Boeing’s Phantom Works division built two of the X-37B spacecraft.
The U.S. Air Force will not comment on what kind of missions the X-37B does in space. The service, which doesn’t mind talking about the space drone as a technological achievement, clams up when discussing actual missions.
Rumors abound. One of the most popular is the X-37B can sneak up and eavesdrop on other satellites. The idea does have appeal, but skeptics point out the U.S. already has other smaller, harder to track satellites to do just that.