The Lewis Ratchet: A Google Notebook explanation.
The Lewis Ratchet. Better name for it would be A Scootch in Space. That's all it is... a simple scootch. Just a quick jerk in one direction... not hard. Don't know why it freaks physicists out so much. It's not my fault God invented water shear.
And in space... assymetric geometry achieves the same thing. You can't scootch in space but you can rotate around your COM. That's a solid anchor to launch off of... that's how CLPP works. I grab on the the Center of Mass of the system and just sling away... simple. Not for muggles but for people who have good math... totally easy.