# What's the point of NASA's impossible space engine? Wouldn't a mirror work better?

My understanding (which is very little) is that the point of NASA's recent virtual-particle engine is to convert solar energy into momentum.

That's fine, but what's the point? If the spacecraft is already receiving solar energy, can't it just carry around a mirror to reflect light and accelerate via radiation pressure?

Or is the quantum version somehow injecting "more" momentum than is actually being delivered via radiation pressure?

• It's science fiction that makes any and all actual scientists laugh at how inept NASA is these days. It makes as much sense as an 8-year-old's superhero-based doodles, so trying to ascribe motive to the design is doomed to failure. Maybe their design has the benefit of squaring the circle and solving the halting problem. Who knows. – user10851 Aug 6 '14 at 5:02
• For more on how silly this whole thing is, see rob's answer here. – benrg Aug 6 '14 at 6:55
• @JohnRennie's link gives a pretty good idea of the concept. Judge the idea however you will. By the way, solar sails do use radiation pressure, and are much less far-fetched. And have been tested. Also, could the Space Exploration Stack Exchange shed some light on why NASA would take this idea seriously? – HDE 226868 Aug 6 '14 at 14:30
• @ChrisWhite and others - By judging all of NASA based on the behavior of one scientist who works there you are just as bad as pop sci media who wrote nonsense such as "NASA validates impossible drive". NASA didn't validate this drive. One NASA civil servant tested it (poorly?) and reported his preliminary findings in a conference proceedings. – David Hammen Sep 13 '14 at 18:47

The engine isn't designed to use solar power. The thrust$^1$ is due to the motion of microwaves within a resonant cavity, and the microwaves are generated by a magnetron on the space ship. The power source for the magnetron would presumably be a nuclear generator or some other compact way of storing energy.
$^1$ if thrust there be