Setting Background I'm working on an admittedly silly sounding setting. Technologically advanced space fairing humans become stranded on a ring of asteroids in orbit around a large planet. They have lost the vast majority of their technology in the process of becoming stranded, but the existing stations keep them alive. They rebuild slowly. The micro-gravity that they live in makes space travel accessible at a far lower level of technological process, and so by the time they have reached what we might consider medieval tech, they are scooting around the vacuum of space in resin-laminated wooden ships propelled by compressed air.
Mechanical Power I've got most of this figured out already. Don't worry about how the ships work, don't worry about how life support works. What I need to know is what these people use as a source of mechanical energy for tasks like milling, air circulation, etc.
Constraints No electricity. No non-human animals of any kind. And no offense to people who are into this, but I am desperately trying to avoid steam power in order to keep this from getting too "Steam Punk". Like the ancient Greeks and many other peoples from antiquity, these folk understand that pressurized steam has force to it, but lack the mechanical precision to make an efficient steam engine - something that took a long time to figure out!
Materials Cast iron, low quality steal, copper alloys, dandelion sap rubber, wood, plant fiber cloths, and leather from human skin. Open to other materials if they make sense for the setting.
Ideas so far
Temperature differential. Exploiting the dark side/light side of the asteroids.
Tidal force. The planet that these asteroids orbit presumably has a very strong tidal force on these little asteroids. Would some sort of crank ratchet pendulum be able to generate a sufficient amount of power?