Yesterday, we reported that the United States Air Force was planning a rather mysterious launch of the X-37B mini shuttle. There's no info on what the space plane is harboring or how long it will be floating around space, although rumor has it the classified mission involves spy satellite sensor testing. The launch was initially slated for earlier this year, but was delayed due to safety concerns.
The Orbital Test Vehicle, more commonly referred to as OTV-3, was delayed after a Delta 4 engine malfunctioned. The X-37B was sent into space via Atlas 5 rockets, but the launch was delayed while the cause of the Delta 4 engine's malfunction was identified to ensure that it wasn't something that could likewise affect the Atlas 5. Ultimately, the launch went off without a hitch.
The X-37B measures in at 8.8m long x 4.5m wide, while its payload measures 2.1m x 1.2m. What the payload is, precisely, is unknown. The space vehicle is about one-quarter the size of a space shuttle, and is a refurbished OTV-1, one of the few official pieces of information offered by the USAF. Its launch will "demonstrate a reliable, reusable, unmanned space test platform for the United States Air Force."
Speculation has it that the hypothetical sensors being tested by the X-37B will be used in CubeSats, which are small, inexpensive satellites that can easily be tracked. Other sources murmur about possible space weapon deployment systems and spying platforms. Whatever its purpose, the X-37B has successfully been sent on its way.