Going Up? 567
jmiyaku writes "The National Post is reporting that NASA has given a Seattle company a $570,000 grant to continue its investigation into constructing a space elevator. Coupled with some production-grade technology from a Japanese car company (carbon nanotube composites), this elevator could be a reality within 15 years..." The Highlift website has some more information.
Optimistic (Score:1, Insightful)
Does anyone else think this is really really optimistic?
Re:Optimistic (Score:2, Insightful)
>>this elevator could be a reality within 15 years...
Does anyone else think this is really really optimistic?
I guess this is why he said "could" and not "will"
Re:Environmental impact (Score:4, Insightful)
The elevator they're proposing is not counterbalanced - this requires it to be even longer than if it wasn't counterbalanced, but it doesn't require a conveniently placed asteroid.
Remember: you're asking what if it falls, right? It is falling. It just happens to be falling at exactly the same rate that the Earth is turning. It's in orbit. In order to make it fall, you'd need to break it.
Re:Good idea for nuclear waste? (Score:5, Insightful)
Basically the problem is that any object we lift from the Earth has energy, and angular momentum. If you want to hit the sun, and not just put it in a very eccentric orbit, you need to remove a lot of energy from the object, and the space elevator wouldn't help - it pulls you out of Earth's gravity well, not out of Earth's orbit. You'd require massive amounts of fuel to get it there.
Re:Better 'mass construction' project (Score:3, Insightful)
A space elevator is a cute idea: it's quite safe, since, well, it's in orbit. It just happens to be in orbit above one spot over the earth (geosynchronous) and really long, so that one side of it touches Earth. And practical? Man. Launch costs go from "huge" to "free". The world would change in a year after this thing being built. Seriously. It'd look like science fiction in no time: space hotels, lunar bases, Martian missions - everything becomes easy.
is it just me... (Score:2, Insightful)
Why wouldn't we have a bunch of satellites in the same planar orbit?
I'm assuming that the elevator gives the sats a ride up, and then simply releases them. Is there another release mechanism that "points" the satellite in the right direction?
Also, could you use the elevator for geosynchronous orbit birds?
A Miasma of Bad Science (Score:5, Insightful)
Wow. There are so many scale errors here it's hard to tell where to start. First, What strain exactly would "snap the elevator in half"? It's a ribbon, and while it's certainly possible to break the ribbon, it's not likely to happen under normal operation, and the design specifies that they'll set it up in a location that minimizes the likelihood of high winds or lightning. Second, "Earth's rotation would slow down"?!? You can't be serious with this. The mass of this thing is so much less than that of the Earth that the slowdown would be indetectable with the most sensitive instruments we have, if we were actively looking for it. To take your example of the figure skater, imagine her spinning, then letting out a one inch long piece of the finest hair you can find. How much do you think she'll slow down? And last, why exactly would slowing Earth's rotation cause us to head for the Sun? The day would get to be more than twenty-four hours, but the speed the Earth moves around the Sun (that's "revolution", not "rotation") would not change in the least.
Go buy a book on physics.
Virg
Re:Great news, but (Score:5, Insightful)
Point 1: Neo to attach to. Unnecessary. You can achieve the same thing with a really long teather and a 1 kg weight on the end. Did you not notice that the cable was 100,000 km long, when geosynch orbit is only 36,000 (miles or km I can't remember, but even if it is miles that would make it 57odd thousand km up, far less then the 100,00 required) the extra thousands of km are used to provide leverage and a decent ratio for the mass to be lifted.
Although I am curious to know what you mean by strong enough. All you need to do is get an object, in geosych orbit, move it to an outer orbit but keep it at the same angular velocity (how long it takes to orbit the earth) and the resulting centripetal force can be used to pull against when pulling up mass. 'Strong' neos aren't needed, a collection of cotton wool would do it, if there was enough and it was far enough out.
Point 2: Constant height. Not actually necessary, the water level is pretty flat (aside from tidal variations due to the moon and the sun) BUT the cable is under constant tension thus would forgive a certain amount of play. In fact the cable has to be at over 5 tonnes of tension at the base to be able to lift the mass required.
Point 3: Energy required for lift. Actually you are wrong again, the energy required is less. When you use a reaction engine fully half the energy required to boost you is wasted throwing mass out in the opposite direction. HOWEVER along with this is the fact that they are going to be using lasers to drive photovoltaic cells to drive electrical motors, and this could (in theory) be purely sunlight driven.
Point 4. Location. The ocean isn't too bad, a simple cargo ship deliver the cargo and it lifts. Sure its not rail or lorry but its good enough. Most of the oil the US needs is shipped via tankers, why can't a few satelites?
Point 5. Anti-gravity. (Ignoring the racist angle) this is an unproven experiment, and it should be noted that 2% is a little different to lifting the item into orbit.
As an aside, the cable itself will weigh in at a stunning 750 tonnes. Of that 480 tonnes (metric) will be above geo-synch orbit (assuming 36k km or should that be Mm???) and not likely to crash down.
I applaude them, but hope it does all work even though I have my doubts...
The tensile strength of the cable needs to be huge.. 7.5 kg per km, and that needs to hold around 270 tonnes, its a hell of a challenge....
Z.
Re:Impact on the environment (and the ground) (Score:5, Insightful)
Re:Good idea for nuclear waste? (Score:3, Insightful)
The subducting seafloor idea sounds much better to me. Drop in into a hole in the ocean floor, and it is pushed into the mantle. No loss of mass for the earth, no huge expenditure of energy, and the waste is taken care of.
You're wrong, do the math. (Score:3, Insightful)
Well, yes, actually.
Consider this: New York city alone produces 13,000 tons of residential waste a DAY, and they've run out of places to put it (Again, Source [fathom.com])... It adds up REALLY quickly.
You're using your intuition, and it's wrong, wrong, wrong.
It doesn't add up. Assume everyone in the world produces as much trash as a New Yorker City resident, and that we double that for non-residental, and that we send all of the trash in the world into space.
That's 13K*(1/.002)*2= 13 million tons of trash a day. To achieve the slowdown you mention (.1 second/day) would take about 1.2*10^16 years. Tidal effects are slowing the earth much faster than that. More to the point, the sun will have blown up by then, making the rotation of the earth moot. Hell, I'm not sure all our protons won't have decayed by then - anybody know the numbers on that one?
Re:Elevator vs. Launch (Score:3, Insightful)
Re:Impact on the environment (and the ground) (Score:2, Insightful)
In fact, when you come down to it, with this system it probably costs as much to bring stuff down (in a controlled fashion) as to take it up, so you would want to minimize how much to bring back. Maybe delicate things like results from zero-G experiments, or people, ride the elevator back down, while other items might be ejected to reenter in more traditional fashion (if the cost of carrying the heat shield up is cheaper than the cost of carrying the payload down).
Re:Good idea for nuclear waste? (Score:2, Insightful)
The romans dumped lots of crude oil into the sea. They were certain it had no practical use for anything. Today we use it for many things from plastics to medicines to fuel.
And we also have a irritating substance to deal with. I hope we have the imagination to see it's potential future uses.
=brian
stupid and wasteful (Score:2, Insightful)
Throw it all in a big pile on the moon. When we need it, we'll know exactly where it is. A few solar powered robots can help dig through it when we need some and set it aside for collection, as well as protect us from the Terrible Secret of Space.