Hermeus demonstrated continuous mode transition with it’s Chimera engine. The test showed that a GE J85 turbojet could operate at up to Mach 3-equivalent temperatures and pressures using the Hermeus precooler, shutdown, bypass the air around the jet engine, and then light the ramjet combustor. This demonstration was performed in approximately 1/3 the time, and 1/10th the cost of equivalent traditional development programs.