The SpaceX Company has repeatedly launched Falcon 9 missiles, which had already flown before. At the moment the record of the company is six flights for the same first stage.
Probably, it turned out to be enough to convince the US military that such missiles could be trusted. According to sources, the U.S. Space Force (USSF) has concluded the first contract with SpaceX, involving the use of the previously flying Falcon 9. In this case, it is a mission to put into orbit the fifth satellite of the GPS III project, which is scheduled for 2021.
It is not yet clear how many more missions of the GPS III project are ahead, but a representative of the USSF said that with the current success, the use of previously flying Falcon 9 will save 52.7 million dollars.