Spin-stabilized Ring Solar Sail.
As I see it, one struggle with launching a solar sail from Earth is that rockets are tall and skinny, but sails need to be broad and flat. So how do you wrap a sail around a spacecraft bus?
What I did was to take the Miura-Ori fold and apply it to a ring. These images show that it works pretty well, to stow a sail and to change its primary plane from parallel to a rocket's main axis to perpendicular to it.
This tube represents a cylindrical bus, and the stowed sail wraps around it nicely. In this model, the tube is 6.5cm in diameter and the "sail" stows down to a 0.5cm ring around the tube (therefore, 7.5cm overall). The dimension of the stowed sail along the side of the tube is 4.0cm.
As you can see, making a hole in the center of a disk, I can fold a 60cm thin-film ring onto a 6.5cm dia tube. The benefit of using the Miura-Ori fold is that when the vehicle is "spun up," the deployed portions pull open the non-deployed portions, all under centripetal force. Want to know more? People are doing real work to get zero-propellant vehicles off the drawing board and into space. See Benjamin Diedrich's site for up to date information. At Frank Ellinghaus' site you can see designs for solar-sails with thruster ring and enhanced payload capability (among other very cool propellantless propulsion technologies). |
