Update 10:08am: SpaceX successfully landed its Falcon 9 rocket back at landing zone one at Kennedy Space Center. Cape Canaveral had already begun buckling down operations ahead of the possibility of Irma on Tuesday, entering what it calls Hurricane Condition (HURCON) 5 status.
We do know that the experimental program is created to help work out the kinks in reusable spacecraft, and there are two X-37B vehicles, built by Boeing.
The secretive program is based in two former space shuttle hangars near the Vehicle Assembly Building at KSC, allowing both spacecraft to land at the nearby Shuttle Landing Facility.
Brig. Gen. Wayne Monteith, 45th Space Wing commander thanked the entire OTV-5 mission team for their efforts in ensuring a successful launch.
The autonomous space craft, blandly called the X-37B Orbital Test Vehicle, is meant to "demonstrate technologies for a reliable, reusable, unmanned space-test platform". Over all four previous missions, the space craft have spent a total of 2,085 days in space.
The payload's mission is classified, but it's a robotic space plan that looks like a mini space shuttle. The X-37B is going to a higher inclination orbit than usual but the X-37B's main mission is classified and is being fiercely guarded. The first one launched in 2010. By comparison, Nasa's retired space shuttles were 122ft long with a 78ft wingspan. An SES official said the launch date will depend on Hurricane Irma's impact on the Space Coast, and engineers are taking precautions to safely store the satellite during the storm.
On its last mission the "spaceplane" stayed in orbit for nearly two years, but it's unknown how long the current mission is expected to last.
A commercial South Korean television broadcast satellite named Koreasat 5A is third in line on SpaceX's launch manifest, with liftoff from Florida scheduled for mid-October.