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The Space Elevator - Public or Private?
AtomicGoat writes "The Space Review reports that a Space Elevator may not get built without help from the U.S. Government, but the notion that 'the DoD can also provide a sense of fiscal discipline when dealing with large, expensive programs' sounds like an Onion story. Right now a small private company (Liftport), not NASA or the Air Force, is in the lead on revolutionary space travel."
Of course it needs government support; you can't just put up an X-mile high tower without worrying about security, shared land use, population relocation, etc. These are all things that government does. Without some government muscle, a private space elevator company would be sunk.
That's a little over twice around the planet, people. Anyone who considers disaster scenarios should think about that. If something goes wrong, there's a possibility that the elevator cable would wrap itself around Earth, hard. Countries under the cable's path probably wouldn't like that. Their governments would make a great deal of noise, just considering the possibility.
Given that the governments are involved to that extent anyway, it's natural to assume that they will also want to oversee construction and whatnot, just to make sure Things Are Done Right. Now, do you want a government with no stake in the elevator watchdogging the process, or one that does have a serious financial stake?
In the same way that soon after the first aeroplane flights had been made, hundreds were being made: Given the high number of competitors and what we have seen so far, I think it likely that someone's going to win the Ansari X prize. Space flight's going to become cheap, and it won't take long for someone private to get a space evelator line up.
Well, people may like to make jokes about $800 hammers,
but the DoD folks are utter geniuses of financial management when compared withother federal agencies such as the FAA
or NASA.
Queue, the correction hordes...
The grass is only greener, if you don't take care of your own lawn.
Great to see space elevator research is starting to pick up. I think its safe to say now that its the only cheap way to space. Governments will have to be involved, as will many companies. Wherever the anchor is will be a huge decision that could completely turn around a 3rd world nation -- or political instability could make it impossible. There's not many "safe" equitorial sites with lots of room for support organization -- look at a map.
The safety issue could really kill it though. If it starts to wrap around the earth, watch out. There has to be a way to "cut the cord" at this and and hope it flies out into space. Of course, a release mechanism like that is a liability in and of itself. So that's a very tough, maybe the toughest, hurdle.
Moo.
Yes, but you still need to worry about somebody flying a plane into it, either intentionally or accidentally. This is something that aircraft carriers are good for. Last time I checked, not that many private companies owned their own aircraft carrier...
"Freedom means freedom for everybody" -- Dick Cheney
Seems to me that every piece of modern technology we have was at one point considered scientific fantasy with countless people declaring that it would never work. Space flight, cell phones, computers, telephones, airplanes, electricity, radio, recorded sound. Every single one of them had problems that could 'never be solved'. And guess what? They were solved.
If you had been at Kitty Hawk, you would have been yelling that the glider would never fly. And as it passed over your head, you would start claiming that they would never get it down.
Technoli
"A ballistic missile can hit a very tiny area, and that is essentially dropped from orbit at high speed, not lowered slowly."
The different between a ballistic missle and a space elevator is huge. It's OK for ballistic missles to reach their target travelling over the speed of sound. That will probably not be OK for the poor fellows (or robots) trying to tie down the Earth-bound part of the tether. Also, a ballistic missle is a relatively discrete package; it is only in one place at a time. A tether needs to exist in many places (i.e. space, upper atmosphere, lower atmosphere) and remain stable in all those environments: much harder to do.
For the initial elevator ribbon deployment, you're talking about 2 spools massing about 20 tons each, but once you've got the initial ribbon up, you use the cheap, cheap, elevator itself to build up the ribbon, so you're not paying typical launch costs for the whole thing.
To get the initial spools and associated hardware up to GEO, Brad Edwards calculates (if an MPD engine is used for the LEO to GEO transfer) that the launch cost could come downn to about $1 billion for 4 Atlas 5 launches -- about twice the cost of a single shuttle mission.
"Just once, I'd like to meet an alien menace that wasn't immune to bullets." -- The Brigadier, Dr. Who
1) This is a great idea; Nasa should scrap the shuttles and build one.
2) The government shouldn't have a space program. (Maybe the government shouldn't have too many programs at all.) This will be an outrageously expensive boondoggle, and we should just let private industry handle it.
3) Dude, when is private industry going to get around to doing that?
4) When it's good and ready.
5) Dude, private industry wouldn't even build the interstate highway system - a fulcrum of America's economy. What makes you think it will build a space elevator?
6) Communist.
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Kim Stanely Robinson has a lot to answer for -- every time the space elevator comes up, people drag up the plot from the Mars books....
To (once again!) answer the objections raised by this scenerio: Unlike Mars, Earth has a nice thick atmosphere. The elevator ribbon has a very low mass per unit length (indeed, this is one of the characteristics that make the elevator physically possible, not just sci-fi). If the cable is severed, only the stuff below the breakpoint would fall to Earth, and execpt for the bottom few hundred miles, would burn up in the atmosphere. The remainder should fall into the sea, and again, because it's so light, any that did somehow hit land would cause any major problems.
"Just once, I'd like to meet an alien menace that wasn't immune to bullets." -- The Brigadier, Dr. Who
Ok, I flipped through the site and couldn't find answer, so I'm going to ask it here and absorb the flames. What holds the orbital end up? Before you say "Nothing... it's in microgravity.", I know. But anything thing that tugs on the ribbon is going to pull the endpoint towards earth. It seems to me that that should have been the first question answered on the FAQ.
Let's see
The government likes to send things into space
The government isn't likely to develop a new technology to send things into space cost-effectively
There is a company that wants to develop a new technology to send things into space
How about the government just promise to use those guys if they prove to be cost effective? I mean a lot of the problem with public funding has to do with people funding things that do not work, or go over budget, in effect, allowing subsidies to make companies take on some of the worse fiscal aspects of public funding.
Why not just reward people who do the right thing, once it's proven they can do it?
And yes, right of ways, air corridors and related ideas are all things the government can help with. But, let's agree to do it as indirectly as possible, lest
1) the project be tainted by political ideas
2) the project become less efficient
These people want to turn a profit, let's lend em the money to do it, and promise them clients, that's what new businesses need. Let's not promise to bail them if they fail, and perhaps, they'll only try once they're sure.
We still have a disagreement regarding scale. Our plumb bob in the tether case is not to be built with string, nor will it have a "hand" which is allowed to move much, nor do we have an overweight "bob" at the end of the tether.
I would suggest a different example to suggest the relative difficulty: hitting a certain tile on the bottom of a swimming pool with a length of sewing thread.
First, I don't think you can just sew it back together. AFAIK there's no "fix" for a broken ribbon.
I've heard the opposite from quite a number of fairly knowledgeable people when discussing this subject. I've never heard your position before your post, although that doesn't necessarily make it wrong. I admit I don't know enough myself to say for sure; maybe at this point nobody does.
Second, if the ribbon is completely broken, the top will go flying into space. Its not just going to keep hanging there above the platform.
Actually, it is. Even if you posit a fairly high-altitude attack with an airliner or a missile, you will cut off, at most, maybe ten miles of ribbon. That works out to less than 1/2000 of the length. Since the ribbon has an exponential taper, it will end up removing much, much less than 1/2000 of the weight, and the center of gravity of the whole thing will barely move at all.
Remember, a space elevator is neither a tower nor a suspension bridge. It is anchored simply to keep it from moving around under winds, small disturbances, etc. but the elevator itself is in orbit. If the anchor is removed, the elevator will stay. Removing a few miles at the end of the elevator is extremely close to simply removing the anchor, and so the rest of the cable will basically stay where it is. It may begin to move slowly, but it's nothing that couldn't be corrected with some small thrusters.
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