Next Big Future - Latest Comments in Improving Space Elevators By Having a Rototating Hoop

Re: Improving Space Elevators By Having a Rototating Hoop

Bob Munck — Sat, 20 Oct 2012 13:41:26 -0000

I roughed out a design for a rotating loop SE on the Liftport forums a few years ago. It assumed a ribbon strong enough not to need tapering. The loop was powered by a large solar-powered "climber" sitting on the outbound side of the loop a short distance above geosynch and forever climbing toward it, without actually moving. There was a large spinning wheel at GEO with its rim moving at the same speed as the loop and in-between its upward and downward legs. You would switch from the loop to the wheel as you went by, then climb down a wheel spoke to GEO.

The ground-side pulley was difficult; it had to be very gentle to the ribbon. I figured some kind of air cushion around a kilometer-diameter semicircle, with lots of redundancy. There was no pulley at the top; the loop just hung out there. The most difficult part, and one problem I didn't have a good solution for, was getting a vehicle onto the loop at the bottom. It had to be moving at the speed of the ribbon, straight up. I somewhat arbitrarily choose a loop speed of 300 m/s, just below the speed of sound. That yielded 32 hours to GEO, which would probably get passengers through the radiation belts quickly enough. (The conventional designs don't, a real problem).

The whole idea is basically science fiction, of course. But it was fun.

Re: Improving Space Elevators By Having a Rototating Hoop

Brett_Bellmore — Sat, 23 May 2009 07:12:18 -0000

Keith Henson's proposal is to use a loop, but to cope with the need for a tapered cable by using pulleys to multiply the number of strands towards the middle. The cable would periodically pass through an inspection station, where it could be swapped out, or re-coated with a film to deal with the effects of atomic oxygen.

Re: Improving Space Elevators By Having a Rototating Hoop

cybrbeast — Sat, 23 May 2009 05:07:00 -0000

Interesting concept. Must look strange to see the such a thing rotating. I wonder what amplitude the rotation will need to have and how much extra strain it puts on the cable.