[colechristensen]

This is very likely either nonsense or something very mundane explained poorly.

Reactionless drives are probably impossible and inventing them would be an earthshattering breakthrough.

Drives "powered" by photon reactions are possible but to get a meaningful amount of thrust you have to produce just an absurd amount of light. (using one in orbit would be a weapon of mass destruction, brighter than the sun, etc)

Otherwise, I don't know, maybe this is something mundane with a little bit of thrust interacting with sparse upper atmosphere gas or something.

[moron4hire]

If anything were ever invented that looked like "reactionless drive", I'm betting dollars to donuts the idea it was reactionless would be short-lived and eventually it would lead to updates in our understanding of matter and what reaction means. Like, maybe some day someone discovers a way to emit gravitons. IDK, I'm sure someone thought the idea of emitting photons without the use of a chemical reduction reaction was preposterous at some point in time, too. But then the reaction would be with space itself. By the end of it, it still wouldn't be "reactionless".