there's a difference between testing the engine, and testing the handling qualities. But not always. For testing the engine which in this case is throttleable

there's a difference between testing the engine, and testing the handling qualities. But not always. For testing the engine which in this case is throttleable and has time constants greater than hundreds of milliseconds the time lag from not having a pilot onboard is acceptable. For flying qualities again the plane is large enough to be slow enough that remote pilot timelag is not significant. There is no part of the envelope of this vehicle where you need a pilot onboard. Most of the development here can be done without pilot onboard. Space has been done from unmanned vehicles since the beginning and what they are doing is only barely rocket science. Putting a pair of pilots in a vehicle with a non-flight-tested rocket engine is just irresponsible. I like Rutan's company. But what they are doing on this program smacks of amateurism. They got engineers killed on the ground and now pilots killed and injured in flight. Both of which were completely preventable by some basic range and flight safety measures. It looks like they are cutting corners by doing too much too soon because of management pressures to cut delays. And people are paying the ultimate price for their hubris.