Super Secret Mini-Shuttle Returns To Earth


The U.S. Air Force doesn't say much about the X-37B Orbital Test Vehicle. 

It was launched May 20, 2015 and was in orbit for 718 days before landing at the Kennedy Space Center in Florida. 

It's an experimental unmanned, reusable space plane. 

The plane caused sonic booms across Florida as it entered the atmosphere.

This was the fourth and longest flight for the vehicle.  It was also the first landing in Florida. 

A fifth launch is expected later this year.