I wonder what the most important potentials and problems are with folding out structures in space. The basic idea is to achieve large structures in space while reducing launch mass and launch volume, and also avoiding human space walking construction work in microgravity. What stress are different kinds of structures in space exposed to? Such as astronauts moving around in them, engines accelerating them.
I can think of three purposes with having big structures in space:
- 1) Parabolic dish for radio telescopes or solar collectors.
- 2) Living space for astronauts.
- 3) Radial distance for an "artificial gravity" centrifuge.
Concerning #1 above, does the geometry of a parabola provide some easy way to "throw out" a foil to get the desired shape, or must it be painstakenly formed inch by inch? And would a thin metal foil work well as a radio telescope dish? Could even a useful mirror for optical telescope be unfolded? Russia has a 10 meter radio telescope in space, the Spektr-R interferometer. It must've been folded out in space.
On #2 Bigelow Aerospace already have two (uncrewed) expandable space stations in LEO and will attach one to the ISS next year. How are they unfolded? They use the term "expandable" instead of "inflatable".
On #3, rotation to create radial acceleration that simulates gravity, large distances are prefered in order to avoid unnatural shifts in weight as crew moves radially. At least a distance long enough that two meters, i.e. standing up, is a practically negligable fraction. I've seen a proposal to use "air beams" instead of wires. An "air beam" is like a hose inflated with air or other gasses so that it gets stiff. It would allow for (human) movements inside of it and doesn't get slack like a wire could. The only actual application of air beams I find today is for tents(!) Would it be a practical technology in space? Here's "some guy's" ideas about air beams for artificial gravity. Slide 10 has an image that demonstrates the strength an air beam can have.