Space Elevator Company Fission

Dag Maggot writes "Highlift Systems seems to be going through some turbulent times with cofounder Michael Laine leaving to form his own space elevator company LiftPort. Interestingly, Liftport pledges to be a "transparent" company, and as such have provided the full text of the original space elevator proposal which was made to NASA NIAC." We mentioned Liftport before, but the proposal is new and quite interesting.

Comments

I think it's more complicated than that

[lingqi]

There are some crazy design specs that people don't usually consider besides the nanotubes and the lack thereof.

1) due to the weight of the cable, it needs to be thicker at the middle and taper off at the ends - this makes the attachment of a vehicle to traverse the cable considerably more difficult

2) the growing - you can't "lower" a cable from a space station. the center of gravity must remain at the geosync point if you want to stay afloat

3) the keeping cable tensioned - this involves capturing a sizable asteroid into an orbit dangerously close to the earth (as in, genocidal proportions if shit goes wrong) - and after you anchor the cable, push it back out so it will keep tension (geosync don't work here). A fly-by capture is out of the question, and actually dragging a asteroid to our doorsteps is impossible by today's figures.

Space elevator, while cool, has a loooong road ahead of it - I am not betting my money on it (within my lifetime, anyhow). Granted I probably seem like a pesky naysayer that's keeping technology from going places - but just imagine stuff we developed WITHOUT first thinking it through; I think the nuclear stockpile on US and Russian sides definitly proves my point.

I'm all for it if they can bring the damn asteroid here SAFELY, though. (Shuttles so far has a roughly 2% failure rate - and that's two completely fatal ones - I don't want the fate of the world depending on that kind of odds)

Re:I think it's more complicated than that

[Raumkraut]

A tapering ribbon makes it more difficult yes, but not impossible. I'm sure there'll be plenty of potential engineering solutions proposed given incentive.

You're right that lowering the ribbon would 'defloat' the CoMass, but extending the ribbon in both directions simultaneously wouldn't unbalance the situation.

What's with the need for an asteroid? There's plenty of matter just lying around the place down here - I'm sure there's a lot of matter which people would pay to have moved beyond geo! Though dangerous (radioactive, etc.) substances would probably have to wait for the first elevator to become operational before being moved to geo...

Incidentally, AFAIK there isn't planned to be any kind of significant station at geo during the construction process - it's unfeasibly expensive to build one without the elevator operational - just look at the ISS! :)

Re:Promising

[Chris Croome]

The space elevator seems to be the most promising alternative to the Shuttle program.

Well, perhaps it'll be an alternative to the generation of shuttles after the next generation, probably though it'll be one after that or even further in the future...

This space elevator idea ain't gonna happen very quicky...

Re:Promising

[wfmcwalter]

Don't get me wrong - a space elevator is an amazing idea, and it's really the only thing that'll deliver the incremental-cost-to-space the space shuttle was promised to do. But don't underestimate the huge scale of the civil engineering project needed to build this, dwarfing the Panama canal and the chunnel. You'd need that next-gen shuttle thing just to haul into orbit the huge amount of stuff. That's geostationary orbit remember, a whole lot higher than the shuttle can go - everything out there boosted itself out with a sizeable motor of its own. Lifting hundreds or thousands of tons of construction material, workers, habitats, air, water, food, etc., is itself a space programme unparalleled in history.

Highlift (et al) are going a vital job - figuring out the basic technology of thie enterprise, writing the real project plan, sketching the logistics, and guestimating the construction cost. Someone (probably someone else) will have to figure out the economics of this thing - when will there be enough traffic wanting to get into space, and at what price, comparing this against the cost of the structure and figuring out when to build, where, and to what scale. Everyone in this phase has an awesome task ahead of them - the planners of the worlds great canals, bridges, tunnels, and dams all had lesser examples from which they could extrapolate - there's never been structure like the elevator, and even your minimal working model is 40 thousand miles long and costs a Dr Evil sum.

Once you get to the construction phase, then you're talking about a huge corporation with major government entanglements (as all great works of civil engineering have a big strategic impact). Canals like those at Suez and Panama were built only once there was a large volume of traffic going the long, expensive way (around the capes) which made the prospect attractive for investors. And the Chunnel and the Oresund link show that just 'cos everyone wants something doesn't mean you get it any time sooner than it becomes (kinda) economic.

Still, it'll happen, just as soon as everyone is sick of going to work in another rustly old rocket.

Re:..yet another tax shelter poisons the beanstalk

[Tackhead]

> U.S. military satellite accident in 1964 (carrying two pounds of plutonium on-board) that burned up on reentry and spread plutonium worldwide = 17,000 curies released into global environment
>Chernobyl Nuclear Power Station accident, 1986 = 810 curies released
>(above figures from www.space4peace.com)
> I believe the next series Martian probe launches are all slated to carry fissionable materials. So we are looking at potentially poisoning the entire population of central Florida as opposed to just a couple of places like Chernobyl and Kiev. That is an order of magnitude higher. A significant improvement.

And how many curies from atmospheric nuclear testing in the 50s?

Answer: several billion which has now decayed to around 400K.

And how much was Pu-239? About 225,000, from the first link.

We've already had your famed civilization-ending release of nasties into the environment. We did it deliberately (We didn't know any better. D'oh!). And yet, we're still here.

We've learned how to make RTGs safe for re-entry so the incident of 1964 doesn't happen again. But more to the point, nuclear power is the only technology with a high enough power density to allow us to extract fuel from the Martian environment for a "Mars Direct" plan.

If you wanna see men (or even long-term surface probes/rovers) on Mars for more than a couple of weeks, it's the only way to go. You can engineer your way around the risks of RTGs. You can't engineer your way out of using 'em.

I don't think you `get' it, no habitats needed

[leonbrooks]

But don't underestimate the huge scale of the civil engineering project needed to build this, dwarfing the Panama canal and the chunnel. You'd need that next-gen shuttle thing just to haul into orbit the huge amount of stuff. That's geostationary orbit remember, a whole lot higher than the shuttle can go - everything out there boosted itself out with a sizeable motor of its own. Lifting hundreds or thousands of tons of construction material, workers, habitats, air, water, food, etc., is itself a space programme unparalleled in history.

That's why they're building this space elevator thingy, see. They send the first strand up in one or two shuttles. Part of the shuttle payload is enough extra fuel to get to GEO. They unroll the strand. They send lightweight climbers up with the next strand. Now they have two strands, the climbers can carry twice as much, and iterate until you have a satisfactory number of strands emplaced.

No habitats, and the ribbon weighs startlingly little per km (something like 7.5kg, OTToMH).