For the first time, SpaceX has launched its Falcon Heavy rocket with US Air Force payload onboard. It's also the first time that SpaceX has launched its Falcon Heavy with reused rockets. This was the most difficult launch ever in in SpaceX history with four separate upper-stage engine burns, three separate deployment orbits, a final propulsive passivation maneuver and a total mission duration of over six hours. The launch was an audition to get SpaceX a potentially multibillion-dollar government contract for future launches.