The X-37B, the US Space Force’s secretive space plane, will soon take flight again. On Monday, the Space Force announced that it will fly the small, Space Shuttle–shaped vehicle on the program’s eighth mission next month. There are two active X-37Bs in the Space Force fleet, both built by Boeing. The second flew more recently, landing at Vandenberg Space Force Base on March 7 after 434 days in orbit. During its most recent flight that ended in March, the space plane launched on a Falcon Heavy rocket for the first time.