The first test flight of the VDR2 engine is expected to take place next year. It will be installed on an unmanned aerial vehicle for the tests.
For takeoff, Stargazer will utilize conventional jet engines, and then, after reaching supersonic speed, it will switch to the VDR2.
If Stargazer ever becomes a reality, a flight from London to New York, which is slightly over 5500 kilometers apart, would take less than an hour.