Prospects for a Space Elevator

Fun video clip from BBC on material science and prospects for a space elevator. 

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Kind of misleading. See here On the one hand, *any* material can be made into a space "cable" so long as it follows the right inverse-hourglass (or symmetric curved spinning top), shape, with an exponential increase and decrease. It will look more like "cloud city" from Star Wars than a cable, so you would need something more like a "climber" than an "elevator" - but it would have the right tension-distribution properties.

On the other hand - to the extent that this is impractical, it is *also* impractical even for fullerenes and carbon nanotubes, even should the technology to spin coherent fibers on an industrial scale ever come into being (another one of those "just around the corner" technologies).

But the fundamental economic question remains. We already *have* the ability to routinely put things into orbit and return to them to earth. It's just a matter of cost per kilogram and orbit-character. The only thing a space elevator potentially gives us is cost savings - but for that to be exciting, one has to demonstrate the clear usefulness, "pent-up demand" of cheaper, more routine orbit deliveries.

So what we really need is a "market-takeover business plan" - the same case you would make to the bank in search of a loan, to see if this idea even makes sense in terms of likely future revenues.

Given our experience with space-economics, we would start with something like a nearly horizontal supply curve that currently intersects the demand curve at the current and longstanding rocket-delivery price - apparently a highly energy-dependent cost that it is not technologically easy to bring down much - at the very least - it hasn't been done to any significant degree in decades.

So, with a space elevator, you would have to have a much lower supply curve, and you would have to show a very flat, almost horizontal, extremely-elastic demand curve, in order to demonstrate the sufficient extra revenues requires to pay the interest on the substantial fixed, and non-trivial marginal, costs of the project.

We should be able to estimate the current elasticity of orbit-demand (bleg to anyone that knows if this already exists out there). If it's not huge - then I think I'm justified in presuming that the space elevator will never get off the ground. First bad pun of the new year.

This is the Royal Institution Christmas Lectures. The first Christmas Lecturer was Michael Faraday. Yes, that Faraday - in 1825. They only missed the years during WWII ever since. They've been televised every year since 1966, and are part of the Christmas tradition here in Britain.

I still remember many of the lectures from the eighties when I was young. Fantastic Christmas tradition, and they come very highly recommended.

Every time I despair about the US competitive situation this century, something like this comes along to calm me. Look at the many audience shots: they show numerous British kids - presumably smart ones - in rapt attention at _a lecture on materials science_ (!) when their time could be so much better spent by them preparing for jobs relevant to the modern age - notably, the skills needed to be a corporate lawyer, an investment banker, a top-tier computer gamer, a reality-TV participant, or a marketing consultant. Yet even though it's "science" and "facts" and they look sincerely interested.

And to think that this furthermore was deemed entertaining to a wide enough audience to be _broadcast_ on national television. Whatever the issues the US may face, we clearly are not as certainly and obviously doomed as the UK is.

@Indy
"But the fundamental economic question remains. We already *have* the ability to routinely put things into orbit and return to them to earth. It's just a matter of cost per kilogram and orbit-character. The only thing a space elevator potentially gives us is cost savings - but for that to be exciting, one has to demonstrate the clear usefulness, "pent-up demand" of cheaper, more routine orbit deliveries."

I only half-listened to the presentation in the background, but I was thinking the space elevator could used for tourism. I imagine those with enough money would pay top sum to go up the elevator. Or maybe I'm horrifically naive.

@cyg
"Look at the many audience shots: they show numerous British kids - presumably smart ones - in rapt attention at _a lecture on materials science_ (!)... even though it's "science" and "facts" and they look sincerely interested."

Don't worry, the attrition rate for the kids will be high once they reach the tail end of puberty and some of the girls out to be hotties and realize they can bask in male attention with or without an understanding of things like materials science, and a lot of the boys will be entirely focused on banging said girls, leaving materials science a forlorn concept.

@Brad Jobs
"There is nothing impossible now in digital age. Anything is possible as long as we put our time and effort into it."

Where is my Jurassic Park then, damnit?

Ok I don't understand why we should invest billions of dollars in to something like this while we still have so many americans who are uninsured. Do I smell wasteful spending?
There are already so many private companies in the US taking on the current day role of NASA. Let them do this, while we invest our tax dollars in improving the infrastructure on the ground.

You don't size the bridge by counting people swimming the river.

I don't think the present-day price elasticity of demand at around $5000/kg says much about what the world would look like if it cost $50/kg to get to space.

I'm skeptical of space-based solar power. You do gain some advantages, like 24/7 operation and no atmosphere, but cosmic radiation will degrade your standard panels by a few percent a year, and you still need to beam the power back down through the atmosphere.

I'd want to see the numbers. La Wiki says a space elevator "could" get us down to $220 per kilogram. Wiki says again you can get about 700 W/kg today, so that's 16.8 KWh per day, or 6000 per year, which is worth about $600. It sounds worth it if all those figures stay set up.

Space solar energy is certainly possible and worth looking into. The main issues you would have, other than maintaining the solar power arrays in orbit, would be that you would need some very large down-link antennas on the ground to receive the transmitted energy (presumably sent in the form of microwaves).

Clearly it's not a production version. There's a natural minimum scale for production versions of these devices, and it's huge - like 5GWe. This might be a pilot plant, if it's not fraud or press-release engineering. $10G is about 200 Falcon 9 launches, assuming zero other spending (and no volume discount).

DoD looked seriously at the concept just a couple of years ago because it offered the ability to roll out a large, hard-to-disable powerplant in a remote area with relative ease. The biggest advantage of space based solar power might be the ease of putting the receiver rectennas in convenient locations, like 20 miles offshore from seaboard cities.

But my bet is that low launch costs come first, not least because any space based solar power plan today has to start with "first we build a reusable SSTO," and that introduces too much risk. Other people will take on that risk in little chunks for different purposes. Revisit the idea in 30 years.

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