Posted: Sun, Mar 6, 2011, 8:42 AM ET (1342 GMT)

An Atlas 5 successfully launched a secretive military spaceplane on Saturday after a one-day delay. The Atlas 5 501 lifted off from Cape Canaveral, Florida, at 5:46 pm EST (2246 GMT) Saturday, after poor weather scrubbed the original launch attempt on Friday. The rocket placed into orbit the X-37B, a prototype military spaceplane on a mission designated Orbital Test Vehicle 2 (OTV-2). This is the second flight of the vehicle: the first X-37B launched in April of last year and landed at Vandenberg Air Force Base in California in December. The X-37 was originally developed by NASA but is now operated by the Air Force Rapid Capabilities Office.