Link: http://mashable.com/2017/05/07/air-...utm_sid=5356feeef9c510f432deea19#mBrLiaAzyaqs
A secretive space plane returned to Earth on Sunday with a sonic boom.
The U.S. Air Force's unmanned, reusable vehicle landed at NASA's Kennedy Space Center after spending a record 718 days in space. Powerful shock waves rippled throughout Central Florida as the mini-space shuttle returned from its mission.
The X-37B Orbital Test Vehicle (OTV) is the military's newest and most advanced re-entry spacecraft. It's part of a broader U.S. strategy to develop out-of-this-world technologies that can be used for multiple launches and landings.
This Earth-circling mission is the program's fourth since April 2010, giving it the moniker OTV-4.
"Today marks an incredibly exciting day for the 45th Space Wing as we continue to break barriers, Brigadier General Wayne Monteith, who commands the space wing, said in a statement.
Most X-37B payloads and vehicles are considered classified, so it's not completely clear what the Air Force is doing with these space planes.
But the Air Force says it has two main objectives: Conduct operating experiments that can be returned to and further studied on Earth, and test reusable spacecraft technologies to support "America's future in space."