238,000 miles is too high for my suspension of disbelief

[redbird]

The American Museum of Natural History is planning an exhibit on the future of space exploration. We are promised authentic old equipment, models, a walk-through diorama of the Martian surface, and information on current space probes.

So far, so good.

They are also offering a "full-size recreation of a lunar habitat" (can you recreate things that don't yet exist?) and a model of a space elevator.

That much is on the web page. The museum newsletter, Rotunda, specifies that this hypothetical space elevator would run from the surface of the moon to about 100 miles above Earth's surface. Passengers or cargo would travel that last 100 miles by spaceplane (which presumably could be launched to connect to wherever the cable is hanging at a given time).

The lunar end of the cable is supposed to be at the South Pole, because there's likely to be water there. That a south pole base makes sense doesn't make it a good anchor point for a space elevator. Yes, there's a lot to be said for a base near the most likely source of water, but that doesn't mean it's a good place to anchor a space elevator.

Furthermore, one of the arguments for building this thing is that it would be a way to get Helium-3 to Earth. Yes, space elevators in the service of nuclear fusion.

The article is by the exhibit curator, Michael Shara, who is described as an astrophysicist. A quick google tells me that his work is on things like the dynamics of dwarf stars. Also, the most recent of the "recent publications" that the museum lists for him is from 2000. He may have been studying engineering and materials science in the decade since, and it's possible that the exhibit will talk about the strains that the elevator cables would need to take, but I am not optimistic. That said, I may go, just for the space hardware.

Comments

[frith]

From the surface of the moon to about 100 kilometers above the Earth's surface... Since the moon's orbit is elliptical and the distance from Earth to moon varies by roughly 42,000 kilometers, what do they propose? A gigantic spool on the moon to reel the elevator in and out? And since they've already gone to the trouble of trying to get this dream space elevator to work on the moon's south pole, why not just dispense with the dream spaceplane and add another 100 kilometers to the elevator? 8^p

[purplecthulhu.livejournal.com]

That's an interesting way to do a space elevator...

The south pole thing is clearly wrong (unless he has a *very* large bearing!) but stretching from Moon to Earth rather than Earth to GEO is an interesting typo. It neatly avoids the main benefit of a space elevator in that you still have to use rockets to reach it!

My suspicion is that whoever wrote the article got the wrong end of the stick, but it;'s not impossible that M Shara got it wrong.

If so, he clearly should be reading more SF!

[redbird]

Since Shara wrote the article, he either got the wrong end of the stick, or really needs an editor. And the spaceplanes are not my idea, they're his: he specifically mentions that Virgin Galactic is working on such.

[kalimac.livejournal.com]

Perhaps the South Pole will also avoid a major problem with any lunar base: it gets very hot on the surface. All the Apollo landings took place early in the lunar morning to avoid that problem.

Also, it should be spelled "re-creation".

[redbird]

Take that spelling error up with the editor of Rotunda; I didn't feel like including a "[sic]."

[kip-w.livejournal.com]

(can you recreate things that don't yet exist?)
Dunno, but there's a Christian theme park that boasts a replica of Noah's Ark!

[carandol.livejournal.com]

That does sound like a terrifically inefficient use of a space elevator (even without it being attached at the south pole of the moon). You only have to compare the size of the Saturn V rocket with the size of the lunar module ascent stage to realise that the fuel-intensive bit of Earth-Moon travel is getting off the Earth's surface. Bizarre!