The Great Space Elevator - Is it possible?

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http://cosmiclog.msnbc.msn.com/archive/2009/08/17/2033079.aspx

I found this article to be very interesting. I doubt it could be completed by 2031, but imagine the plus side of it if or when it ever does get completed?! Though I'm sure debris and junk in space could cause all kinds of damage...

 

It would be great until some snotty-nosed little brat comes along and presses all the buttons before he leaves...

 

Realistically, the only significant obstacle left today is carbon nano-tube lengths. I don't even think the power issue will remain if we can get those, as carbon nano-tubes also happen to be some of the best conductors known to man (and in space may well act as superconductors).

Space debris may become an issue, but with modern plasma research, I don't think it'd be an insurmountable one (we're not too far away from having functional plasma shields).

The guy talking about building one by 2031 is probably an idiot (we have no idea when or even if we'll be able to grow carbon nano-tubes of sufficient length), but the time-line isn't entirely impossible.

Tal, today, at least we know the answers to most, if not all, of the 'how' questions. We just don't have the capacity to realize them yet. I don't think it's too much of a pipe-dream any more, but more like controlled fusion: worth a lot of hard research into getting it done.

 

That's what she said.

Ba-doom boom...

 

I think I read some SF books where they had these things and they solved the problem with crashes by somehow making sure that if there were any breach the entire thing would go out into space instead of crashing down.

 

I get claustraphobic going more than 3 floors in a lift!

 

Only in Sid Meier games.

 

Well, the stresses already on the cables just to keep the station in place are already high enough to demand a material stronger than anything that currently exists in viable form, so I'm guessing any kind of damage to them that would threatedn the station would have to be pretty massive. I mean, flying a plane into taut carbon nano-tube cables probably wouldn't do anything other than damage the plane. Likewise, a category 5 hurricane probably wouldn't damage them any either (though the elevator would obviously be grounded).

Add to that the fact that any system logically designed would put a slight positive pressure on the system (meaning the station is at least a little beyond geosyncenous orbit, and thus any damage to the lower ends of the cables would only pull the whole system out, and your only real threat is to the station itself (the elevators, while potent terrorist targets, would likely be pretty small in the end, and easy to protect from most disasters).

Now, with that in mind, let's look at the station and it's threats. Assuming any kind of reasonable control on who goes where, there's not much threat of terrorist attack (how much do you worry about it on the ISS today, after all). It could be targeted durring a war, but then so could anything. The only natural disasters out there would be impacts with either orbital debris or meteorites, which are what the plasma shield is for. Honestly, your biggest threat would be a construction accident of some kind, and again, simple safety precautions can minimize that threat to damage to the station itself (as opposed to destabalizing it's orbit or the like).

Indeed. The original idea was to put the station in geo-synchrinous orbit, as to minimize the strain on the cables, but that actually leaves it remarkably sensitive to any changes on earth. At that point, anything pulling on the cables in any way would pull the entire station down, albeit slowly. A much better idea is to put it a little beyond (or if the cables can handle it, far enough beyond to simulate 1G). The entire station then experiences a slight tidal pull away from the Earth, which is countered by the cables. If the cables pull it in, the station's pull counters that and brings it back out. If the cables are severed, the whole thing, station and attached cables, slowly drift out (hopefully slowly enough for a rescue attempt). Even if that damage were due to a hijacked 747 impact (and assuming that could sever them), you're likely not looking at more than 10 miles of thin cables. They'd totally destroy anything they hit, but you're talking about individual cars or people here, not city blocks. Plus, if you located it costally (especially on an island or at the end of a peninsula), there are high odds the cables would only hit the water anyway.

 

Some may say this is a railroad into space but I think it is more of a space pier. Like a pier goes out from the shoreline to a boat so you can easily board it and drive away a space elevator would be a possible way to get to some level of Earth orbit beyond the atmosphere.

I think the idea is worth looking into. It could massively cut down on both the cost and pollution per pound of items or people taken to space. That is if it works. Still worth a try considering the savings.

I know I derided the "railroad" part of the title but one thing that is worth noting is that today railroads can haul things cheaper and with less pollution than a truck on a road. Thus high initial investment costs are paid off via long run savings.

It it works then great and it could economically serve a similar function as a train-though I still like the "pier" term better. After all if it becomes cheaper and easier to put things in orbit then why not increase the size of those things until you have functional space liners floating around both taking on new people and supplies.

PS Yes, I too am a fan of Sid Meyer's games. I found out that Alien Crossfire has a bug (or did when I played). It doesn't really have a way to comprehend what ending to show for the game if there is a cooperative victory for an alliance between one of the alien factions and human. Won it playing as the Caretaker Marr and the game crashed upon my victory because I had a functional pact with at least one group of humans. The game is great and very intelligent in many ways. It is just that I'm surprised to see someone helping develop it didn't stop to ask what would happen if someone tried _____.

 

Next thing you know there'll be a theme park on the moon with black jack and hookers....in fact, forget the hookers!

We're whalers on the moon, we carry a harpoon...

 

Pplr, I've never heard a space elevator called a 'railroad'. Yes, I think a pier would be a much better analogy, as the space elevator won't actually get us anywhere we really want to go, it'll just get us to the environment that can get us there.

Silvery, I think it's "in fact, for get the blackjack". Bender likes hookers!

 

Citation needed.

300 times, maybe. Thousand times? Where do you get that number from?

 

The Alley is sure taking a turn for SF lately

It's a fun read and it's a fun concept, but as an actual structure built? I see several problems. First, no matter what, not in the next 15 years, not even by 2031, not in anyone's dreams. Second, the carbon tubes make it sound like it's feasible, but that's assuming they can be grown to this length. For now they can't and I don't see any indication that they ever will be (not to mention they're rather flimsy, as the article itself points out). Third, how do you protect the elevator once it's up? NOG mentioned plasma shields, which sounds really cool until you think about the size of the thing. I don't even want to think about how much energy a shield spanning a hundred thousands kilometers will need, never mind that with current technology the shield is tiny, needs a strong electromagnetic field, and can withstand very little pressure. Fourth, this is NOT going to cost just 10 billions dollars but much, much, MUCH more (at a conservative estimate I'd place it at half a trillion). And finally... what exactly do we need this thing for? I'd be an amazing technological achievement, but the actual practicality compared to how much it will cost and how long it will take to build escapes me.

From the article itself, which says they're aiming for 100,000 miles.

 

Ziad, the practicality is simple: (relatively) cheap and easy access to space. With a real space elevator built, and an orbital contruction yard (the next logical step), we could feasibly colonize the moon without too much practical trouble (a few technical problems remain on that note, but the practical side would become a cake-walk). We could probably even ship all the food and water needed for the colony. Add to that the capability to make manned ships that can travel to Mars, Mercury, Io, and beyond. Basically, a space elevator would give us fairly ready access to the Solar System. Interstellar travel would still be a problem, but with the potential for a station on Mercury, solar sails would be looking a lot more feasable.

 

are we, who normally deal with realistic debates seriously discussing whether or not this is possible?

Im going to have to paint my dog blue.

 

Exactly - even carbon nano tubes have only had tensile strength studies done on a micro-scale. There is currently no known substance you could make the cable out of that would be able to support the weight of the cable itself.