X-37B Breaks Record, Lands After 780 Days In Orbit! As of today, the total number of days spent on-orbit for the entire test vehicle program is 2,865 days. This is the Air Force’s premier reusable and unmanned spacecraft, providing the performance and flexibility to improve technologies in away that allows scientists and engineers to recover experiments tested in a long-duration space environment. The X-37B Program performs Risk Reduction, Experimentation and Concept of Operations Development for reusable space vehicle technologies, all at the extreme level of being highly classified. The Air Force is preparing to launch the sixth X-37B mission from CCAFS in 2020.