US Air Force's Secretive X-37B Space Plane Nears Day 500 in Orbit
• http://m.space.com, By Leonard DavidThe U.S. Air Force's mysterious robotic X-37B space plane is sailing toward the 500-day mark in Earth orbit on a secret military mission.
The U.S. Air Force's mysterious robotic X-37B space plane is sailing toward the 500-day mark in Earth orbit on a secret military mission.