Orbital elevators and long, long days

Langy · 08-16-2009, 01:21 PM

And on the original topic:

An orbital ring is a type of space elevator that doesn't need to go out to Geosynchronous orbit (or even be on the plane of the equator). I think this is the 'pinwheel' concept mentioned earlier, though that isn't a term that's usually used as far as I know (or could find out with a quick Google search).

With an active off-planet industry already in place, an orbital ring isn't too expensive either, at least according to the original designer's calculations - only a few billion dollars, though the Wiki article doesn't mention how much of a payload they can carry.

When compared to real-life orbital elevator designs, the ones in GURPS Ultra-Tech are extremely expensive - an order of magnitude or more off from the calculations done by experts in the field, if I remember right. Mind, said experts might be biased, but I'm fine with optimistic projections in my sci-fi.

EDIT: Specifically, the orbital elevators in Ultra-Tech are $40 billion per ton per day. In the design that I've got here sitting in my lap, the projected budget was $6 billion dollars for a 4.45 ton per day payload cable (it's a 6.85 ton per day total cable, but the climber masses 7 tons - there are roughly one climber sent up per 3 days, though an actual trip takes 7.5 days total). Construction time was 30 months, total capacity 20 tons with a 13 ton payload, and 125 trips per year. This comes down to $1.35 billion per ton per day for the first cable. Cables after that were priced at ever-decreasing rates, with the second at $0.5 billion per ton and built in 6 months. The third cable was priced at $5 billion for a 140 ton payload at 125 trips per year - or a price per ton of payload per day of $100 million. The fourth was the same size but cost $80 million per ton per day.

The lower prices are due to bootstrapping - using the earlier built elevators to lift the new cable up into orbit.

08-16-2009, 01:21 PM	#11
Langy Join Date: May 2008 Location: CA	Re: Orbital elevators and long, long days And on the original topic: An orbital ring is a type of space elevator that doesn't need to go out to Geosynchronous orbit (or even be on the plane of the equator). I think this is the 'pinwheel' concept mentioned earlier, though that isn't a term that's usually used as far as I know (or could find out with a quick Google search). With an active off-planet industry already in place, an orbital ring isn't too expensive either, at least according to the original designer's calculations - only a few billion dollars, though the Wiki article doesn't mention how much of a payload they can carry. When compared to real-life orbital elevator designs, the ones in GURPS Ultra-Tech are extremely expensive - an order of magnitude or more off from the calculations done by experts in the field, if I remember right. Mind, said experts might be biased, but I'm fine with optimistic projections in my sci-fi. EDIT: Specifically, the orbital elevators in Ultra-Tech are $40 billion per ton per day. In the design that I've got here sitting in my lap, the projected budget was $6 billion dollars for a 4.45 ton per day payload cable (it's a 6.85 ton per day total cable, but the climber masses 7 tons - there are roughly one climber sent up per 3 days, though an actual trip takes 7.5 days total). Construction time was 30 months, total capacity 20 tons with a 13 ton payload, and 125 trips per year. This comes down to $1.35 billion per ton per day for the first cable. Cables after that were priced at ever-decreasing rates, with the second at $0.5 billion per ton and built in 6 months. The third cable was priced at $5 billion for a 140 ton payload at 125 trips per year - or a price per ton of payload per day of $100 million. The fourth was the same size but cost $80 million per ton per day. The lower prices are due to bootstrapping - using the earlier built elevators to lift the new cable up into orbit. Last edited by Langy; 08-16-2009 at 02:03 PM.