Wednesday, September 21, 2005

Thank you, Glenn, for pointing out the blindingly obvious to people who really ought to know better.

$100 billion just to go back to the Moon? For what? Is there suddenly a critical shortage of moon rocks that threatens to wreck the economy? No, wait -- I know! We've just discovered there's trillions in oil on the moon! And no environmentalists or medieval regimes! A huge cache of diamonds, perhaps? The secret to a grand unification theory of relativity and quantum mechanics?

No, sadly, there is no reason to go back to the Moon, except that it's there. There is, however, a reason we never went back: it's a big, airless, resourceless, useless hunk of rock that costs $100 billion to get to. We have rocks here on Earth. They cost a lot less than $100 billion to get to.

A space elevator, otoh, not only serves a useful function (imagine that, a space program whose primary objective is something that's actually useful), but would be an epochal achievement like the Moon landing of our parents' generation and the Panama Canal of our grandparents' rolled into one. Not only would it be a tremendous achievement in and of itself, it could serve to usher in a new era of low cost orbital transport. Just imagine how the world will change if satellites can be put into orbit more reliably than today for a tenth to a hundredth of the current cost.

Now, I understand why NASA has not yet fully embraced the space elevator concept, though they are looking at it, including sponsoring a competition for the "climber" portion of the elevator. When I introduce the concept to engineers for the first time, they give me a look like I've just claimed Elvis has been living in my basement all this time -- till they see the white papers. Then they scratch their heads and say "Wow, that might actually be do-able." In the end, it still may prove not to be feasible (though that looks less likely every year) but at the very least NASA owes the idea a few billion in development money. It's a lot better than wasting $100 billion on a been-there, done-that boondoggle.

Best case: sometime in the next couple years, NASA says the space elevator looks promising enough that they cancel the whole "Operation Do What We Already Did 50 Years Ago" and divert that entire budget into building a half-dozen to a dozen space elevators.

UPDATE: It occurs to me now that if the space elevator comes in anywhere near its projected budget, the cost of going to the Moon would probably actually be less if we diverted part of its budget to making a space elevator to help us get to the Moon. As Glenn points out, most of the energy cost is getting into orbit.


Anonymous KeithCu said...

I agree that this is blindingly obvious.

I also think that going to the moon and mars is fine, we just need to make it affordable.

I posted an article with more thoughts here: with most of my data coming from the Edwards-Westling book called "The Space Elevator" which I recommend people read.

9:09 AM  
Blogger TallDave said...

I agree Keith, it does make sense when it's cost-justified, which the space elevator would go a long toward toward providing.

Thanks for the book recommendation.

9:26 AM  
Blogger TM Lutas said...

One thing that is on the moon is nearby real estate that has no atmosphere on it. Solar power, when not attenuated by atmosphere, is actually not a bad deal and lunar solar power is one possible way out of the problem of getting the huge amount of energy needed to bring everybody on the planet to 1st world levels. The power would be shipped back via microwave.

Space elevator or not (and I'm a big fan), it's likely going to be cheaper to send up a factory to the moon and build from local material rather than lift everything even if it's at $100/kg space elevator rates.

10:43 AM  
Anonymous Jon said...

The energy cost of getting into orbit is insignificant. What costs real money is developing new vehicles and support infrastructure.

Building space elevators is a nifty notion but doesn't do anything about getting you to somewhere beyond earth orbit, so we'll still need new vehicles even if they are built and operated successfully.

10:56 AM  
Anonymous keithcu said...

Jon, you make a few good points.

Yes, the only thing a space elevator does is dramatically cut the cost of getting something into orbit from the current price of $10,000 per kg.

It can be used to get us to other places if we build elevators on the moon and mars. Once we've built the first ones, the future ones become much cheaper. It might be that we bootstrap explorations with this mechanism. Then, the only thing we need are vehicles to get us from one space elevator to the next and those could be a simple box, something very different from the monstrous Apollo-style systems we are building.

Once we build a space elevator, it puts us all through a rabbit hole and changes everything. This is a good thing.

11:32 AM  
Blogger TallDave said...

lutas: Thanks for the thoughts, but I doubt it. The local materials need considerable processing to be at all useful. Plus, empty space is fine real estate for solar power. I do agree that space solar power makes a lot of sense at elevator prices.

12:46 PM  
Blogger TallDave said...


By far the biggest reason the vehicles are currently so expensive is because they have to achieve and survive blast-off and re-entry. A gentle, cheap ride up and down the elevator probably reduces the costs by 90% or more.

Once in space, they need only the gentlest of propulsion units, because there's no loss to friction. It's a much easier engineering issue.

12:50 PM  
Blogger TallDave said...

Good point keith. Spacecraft lifted by elevator don't need to be the slightest bit aerodynamic. That's gotta help.

12:51 PM  
Blogger HaloJonesFan said...

Space elevator?


Excuse me, I just...AHHAHAHAHAHAHA!

Ridiculous. "It's a very simple concept! All we have to do is develop the technology!" Yeah. We have to invent a new type of matter to do it, too, because the tension numbers in that cable are going to be large. Oh, and this cable is going to be TWENTY-THREE THOUSAND MILES LONG, and possibly even longer than that. People, that's all the way around the planet, and then some.

"Space elevator". Right. You know, levitation systems powered by quantum fluctuations would be even more efficient than a space elevator! Shouldn't we divert some of the funds from this space elevator project into antigravity research?

Jesus, you nerds are hard to please. For the past twenty years you've been bitching about how we don't have Heinlein-style moonbases. Now we've got a plan to go back to the moon--but it's based on actual physics and not The Star Trek Wars of the Twenty-Fifth Century, so you don't like it.

1:37 PM  
Anonymous KeithCu said...

HaloJonesFan, you can ignore the science if you want to, but nanotubes are strong enough, and they were invented in 1991 which by math is not in the 25th century.

Go to and read my article for more facts. One thing I mention there is that nanotube the width of a hair is strong enough to lift a car.

Materials science is an important part of building the space elevator and will help mankind to make major progress in that area.

In 1960, going to the moon seemed like science fiction. In 2005, a space elevator seems like science fiction. I want mankind to attack problems which seem like science fiction.

2:12 PM  
Blogger HaloJonesFan said...

>but nanotubes are strong enough,
>and they were invented in 1991...

Ha. Now all we need to do is make an arbitrary number of nanotubes that are twenty-three THOUSAND miles long. Bit of a problem there.

2:29 PM  
Blogger TallDave said...


Again, a lot of engineers have responded that way, until they read the white papers.

Actually, we did invent a new tye of matter. It's called "carbon nanotubes." The engineering calculations have been done, and the engineers now believe they will in fact work. All we need is something like a 50% carbon nanotube composite.

3:41 PM  
Blogger TallDave said...


Each one doesn't have to be that long. There are plans for how individual lengths of 10 - 100 meters will be connected.

Even a few years ago, it was still considered impossible, because no one could make more than a few grams of nanotubes. But industry was unexpectedly successful in mass-producing nanotubes.

3:43 PM  

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