An Atlas V rocket is scheduled to blast off from Cape Canaveral at 11:05 a.m. Wednesday, carrying a mini-shuttle on a secret mission.
The Air Force’s X-37B mini shuttle has been to space three times before. It even stayed in orbit for almost two years.
The Air Force won’t say much about what the X-37B does once it gets into space. It will fly in a low orbit around the Earth and is controlled like a drone, landing on a runway like an airplane.
Wednesday’s launch will be the beginning of its fourth mission.
The last time it launched was December 2012 in the nose of an Atlas V rocket. It didn’t land until a record-shattering 22 months later.
The Atlas V will also carry 10 tiny satellites.
When released, the satellites will test whether the sun’s energy can be used to power a spacecraft.
The shuttle is set to ride into orbit on top of the Atlas rocket’s second stage, called the Centaur.
The 10 satellites will ride on the bottom of the Centaur inside a compartment called the aft bulkhead carrier.