US Air Force's Secretive X-37B Space Plane Nears Day 500 in Orbit
Monday, April 21, 2014 - 13:00
in Astronomy & Space
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. The X-37B space plane launched on Dec. 11, 2012, and is out the Orbital Test Vehicle 3 (OTV-3) mystery mission.