Anyone tried the caffeinated soap off thinkgeek?

What would be a super-cool propulsion/reorientation system for a satellite? I work with a group of guys out in california that are experimenting with a wator vapor hot gas propulsion system... it is fairly low power, but it only provides milli-newtons of force.

So i'm thinking, what could we build that could reorient a satellite in the most powerful way possible? Of course, a combustion engine will do that. Combustion engines, however, need to have a flammable liquid or gas to combust. In space, with things floating around everywhere just waiting to hit your equipment, a tank filled with combustive material may not be the best idea of a thing to have.

Spinning ball bearing systems are great. They seem to put out a lot of direction - changing torque for a fairly small device. I have no idea as to the power requirements of these devices. I can imagine they would be fairly high, even with a really high quality lubricant to allow the bearing to spin.

So whats next? I guess it would depend completely on the application you need it for. Eventually you want to get something you can use to, say, land on the moon, with no combustion. A nice trick. Maybe impossible, depending on the gravity of the situation (ha ha).