by the following technology flight vehicles: HTV-1, HTV-2, and HTV-3X leading to the HCV vision vehicle. Due to manufacturing issues with the HTV-1 originally proposed one-piece carbon-carbon aeroshell, work on HTV-1 did not continue beyond CDR. HTV-2, a higher endurance and more capable vehicle, was pursued with a 'Design for Manufacturing' approach to the aeroshell.

The Falcon HTV-2 program had two test flights, both ending within approximately nine minutes from launch. Both these tests were funded by the US Defense Advanced Research