LiftPort Wants To Build Space Elevator On the Moon By 2020 210
Zothecula writes "When the late Neil Armstrong and the crew of Apollo 11 went to the Moon, they did so sitting atop a rocket the size of a skyscraper that blasted out jets of smoke and flame as it hurtled skyward. For over half a century, that is how all astronauts have gone into space. It's all very dramatic, but it's also expensive. Wouldn't it be cheaper and easier to take the elevator? That's the question that Michael Laine, CEO of LiftPort in Seattle, Washington, hopes to answer with the development of a transportation system that swaps space-rockets for space-ribbons. LiftPort ultimately wants to build a space elevator on Earth, but the company isn't planning on doing it in one go. Instead, Laine and his team are settling for a more modest goal – building an elevator on the Moon by 2020. This is much easier. For one thing, there’s no air on the Moon, so no icing problems. Also, the lower gravity means that no unobtainium is needed for the ribbon. Kevlar is strong enough for the job. And finally, there’s very little in the way of satellites or debris to contend with."
Space elevator orbiting the moon? (Score:1, Informative)
First post? Anyway, you can't "anchor" a space elevator to the moon from lunar orbit. It would have to stretch all the way to the Earth - or at least to a Lagrange point.
There is one problem... (Score:5, Informative)
That problem is that there is no way to create a lunar-centric orbit where the upper terminus of the ribbon hovers over a fixed position. So any tether can not be fixed to the ground. So lifting anything with that tether will involve something like a skyhook catch, except it will be at orbital velocities.
Re:Space elevator orbiting the moon? (Score:5, Informative)
They said Space elevator. Space elevator "orbiting the moon" are your words. This link shows exactly what they are attempting to do: http://www.gizmag.com/lunar-elevator/23884/pictures#2 [gizmag.com]
Re:er.. does the moon rotate fast enough?? (Score:4, Informative)
The moon does not rotate. When you look at the moon the same side of the moon always points to the earth. So, the ribbon would need to be held stable by Earths gravity to some extent (it seems).
Our moon does rotate, with a period equal to its revolutionary period about the earth. This kind of synchronization is common with moons of planets, and is caused by tidal forces between the moon and the planet.
Re:Just build it horizontally (Score:4, Informative)
Space elevators also allow you to bring things gently DOWN from orbit. How's that mass driver gonna work for ya?
It could work quite well. Mass drivers can decelerate as well, and can recover and convert the kinetic energy to electricity in the process.
Re:There is one problem... (Score:5, Informative)
Having read TFA, this seems to be precisely what they're doing [gizmag.com]; it looks like they deploy at the L1 point and extend the tether in both directions. Of course, this does mean the tether needs to be an extraordinary 250000km long.
Despite being totally awesome (which is reason enough to do it!) and also good practice for Earth (ditto) I am slightly at a loss as to how useful this would be. Space elevators are slow, and a lunar elevator would be really long and therefore really slow. And it's not as if the moon's hard to land or take off from.
I'm wondering if there's something useful to do with the other end. The high end of the tether is only 135000km from Earth. Is that far enough into the ionosphere to use for power generation?
Kickstarter campaign! (Score:5, Informative)
You put LiftPort on the front page and forget their KickStarter campaign?
It started on the 23.08, and in 5 days it's raised $27.514 of the 8000 goal.
http://www.kickstarter.com/projects/michaellaine/space-elevator-science-climb-to-the-sky-a-tethered [kickstarter.com]
Re:One other thing a Space Elevator needs... (Score:5, Informative)
Why deal with dust at all? Put your scope in space.
The temperature extremes are much worse on the moon - close to absolute zero to hundreds of K if my memory serves right . In space, you just put your scope at L2 or Earth-trailing, build a passive solar shield (or use a cryopump if you need really low temps), and point it away from the sun. Voila, constant temperature and 100% duty cycle. Put your scope in space.
There's also the fact that during the two weeks of duty cycle where you can operate the scope, you don't have solar power, so you have to have some way of storing energy. A telescope in space just uses solar panels and gets power 24/7. You'll have to cool your electronics half the time, and heat them the other half, so again, power, and storage. Go ahead, say nuclear. My understanding is that the moon has very few heavy elements, so all that has to come from Earth. So add a nuclear reactor, RTG, or batteries to your expenses.
Telescopes on the moon have to have pointing mechanisms, and the moon has gravity, so it's more mechanically complex (dust, vacuum). Telescopes in space have reaction wheels and thrusters to control pointing. No dust, and also few moving parts in vacuum. Much simpler. Put your telescope in space.
That is, in fact, why we are putting our telescopes out at L2 or Earth-trailing. Hubble would have been there had it not been for the mandate that it ride the shuttle. Have you noticed that we're not putting telescopes in Earth orbit anymore? It's not because we don't have the shuttle. It's because Earth orbit is sub-optimal, and not just a little bit.
As far as comparing astronomy on the moon to astronomy on Earth, well, Earth has a lot of advantages for telescopes, and that's why there are lot more of them here on Earth than there are in space. Not least that you can breath the atmosphere and find cheap places to sleep and have grad students pull the late night shifts. There are of course disadvantages, and you could never have JWST on the ground, but the moon is just not a great place for telescopes. I'm not entirely talking out of my ass here. I've sat in the rooms where these tradeoffs were made, and the moon gets put on the list. Then we start ranking. The moon ranks low in performance (duty cycle, power), high in cost (humans in space suits have to build it, everything has to be shipped from Earth), and high in risk (you have to ask why, srsly?). Then by the wonders of Excel, the moon drops to the bottom of the rankings.
But it is considered.
That's even assuming we had the capability to build a telescope on the moon. Which would be insanely expensive. Humans building telescopes, launchable or not, where they can breathe is always going to be way cheaper than building them on the moon.
Care to link to any peer-reviewed documentation that shows the abundance of He3, or any other interesting mine-able elements on the moon? I am ignorant of the geology of the moon, so if there's evidence that there are mine-able elements on the moon (including He3), I'd be happy to have my ignorance lessened.
You haven't really addressed the question of you know, actually having a working fusion reaction that needs He3. We don't. And probably won't any time soon. What are the economics of mining something we don't yet need and is difficult to store?
Re:Space elevator orbiting the moon? (Score:2, Informative)
Astonishing!
Re:well that's just silly (Score:2, Informative)
I think you've missed bertok's point.
He3 is a waste product from D-D fusion. And D-D and D-T fusion are much easier than He-3 fusion. So if we ever achieve commercial He3 fusion, we'll have already had D-D fusion for decades. And since He3 fusion requires higher temperatures/pressures (ie, better confinement), the same technology would make D-D and D-T fusion more efficient/compact. Which means that even as He3 fusion displaces D-D/D-T for big power-stations, they'll move into entirely new markets (such as mobile power plants. Ships/etc.) And the process repeats, each time you improve He3, you improve D-D/D-T fusion even more.
But it's more than that. If we have fusion, it would be massively useful in space. So if we have the infrastructure on the moon necessary to mine the extremely trace amounts of He3 from the regolith, we'd have a lot of fusion power plants on the moon. And He3 is a waste product of D-D fusion...
So even after Earth bans D-D fusion, it would be cheaper and easier to do anything else in space and just export the He3 waste from their own fusion plants, than to mine He3 from the regolith.
He3 just isn't a reason for going to the moon. (And I say this as a space fanboi.)