I encountered this reddit post, which is a video of a test of some sort of device hovering precisely in place & maneuvering using some slightly underexpanded reaction control system. I'm also assuming there's some reaction wheels aboard, as it yaws without me seeing any corresponding plumes.
A commented added:
This is actually fairly old technology developed during the Cold War. It is designed to be used to intercept incoming ICBM’s in space.
I find this very unlikely for multiple reasons:
Why would such a system require such a precise maneuvering control system? To be able to hover like this is no small feat of control systems design.
Why would it have such limited reaction mass? In the video it burns out quite rapidly. To reposition to intercept an ICBM would not only require about a zillion of these things in orbit over the US at all times, but likely a massive amount of dV on each to be able to rapidly reposition to where a collision would occur.
The video quality seems too good to be from the 50s-80s.
It doesn't look like a vacuum optimized system. Sure, maybe it's just missing some nozzle inserts, but the thought was still in my mind.
I can't find anything on this through some cursory google searches. So I turn to you guys.
What the heck is this thing?