Space Elevator pilot program?

PurduesUSAFguy · 2004-06-26 17:12:34

Hi,
I was just wondering what kind of mass we would be talking about and strength requirements for just a small proof of concept ribbon that wouldn't have ot be payload bearing. I think if we showed that it is possible to have something stretching into space it would go along way to eleaviate(sp?) the 'giggle factor'.

MarsDog · 2004-06-26 17:21:46

http://www.usatoday.com/tech/news/2004- … m]Elevator to space in 15 years ?

Estimate by US researcher.

Rxke · 2004-06-27 01:40:16

I'm afraid there's no such thing possible as a small scale proof of concept...

Deployment of the minimum required strenght ribbon is still years away... Of course, you can test the cable-cars etc on pieces of ribbon-esque stuff, hung from towers etc, but that's not a proof it will work.
Proof of concept would be deploying a cable that is approx 60000miles long, to keep it up (centre of mass must be GEO, so either you build a crazily heavy sat/counterweight in GEO, making the weight of the cable insignificant, or you build a lighter one, further out (2x GEO alt)

mboeller · 2004-06-27 05:32:11

I'm afraid there's no such thing possible as a small scale proof of concept...

Sure you can do it.

Start with an spinning tether facility in Low earth orbit like the one in development from http://www.tethers.com.]http://www.tethers.com. Links:

http://www.tethers.com/LaunchAssist.htm … ssist.html
http://www.tethers.com/papers/HASTOLAIA … APaper.pdf

When you have gained enough experience you can move on to an real tether in low orbit. Links:

http://www.affordablespaceflight.com/]h … light.com/
[edit] forgot this link : http://members.aol.com/Nathan2go/]Space Tethers for Space Tourism

From here you can start build an complete tether.

With this incrimental approach you gain already a lot cause you can reduce the speed requirement to reach orbit from 100% down to ~70% so the payload for such an suborital SSTO or better SSTS vehicle would be far higher than with an normal SSTO or any RLV. This in the end will lower the price for payloads so much that the building of an tether in GEO-orbit becomes feasible.

Rxke · 2004-06-27 06:11:36

Depends on what you see as 'proof of concept,' of course...

Sure you can do *a lot* of preliminary stuff, but a spinning tether (A.K.A. Skyhook) , while using similar hardware, is not a Space elevator, the dynamics are totally different. Space elevator has one fixed point on the surface, Skyhook has none, for starters...

BTW, i do believe in the elevator, but i'm afraid the nanofibre research will prove more difficult/expensive than predicted...

mboeller · 2004-06-27 13:17:56

Sure you can do *a lot* of preliminary stuff, but a spinning tether (A.K.A. Skyhook) , while using similar hardware, is not a Space elevator, the dynamics are totally different. Space elevator has one fixed point on the surface, Skyhook has none, for starters...

I don't agree.

IMHO you can use Tethers for much more than an "big" space elevator only, and you don't have to wait for the big breakthrough to get long and perfect nanofibres to make all the other systems work. Most of them work with todays materials or with slightly better fibres. Look at http://members.aol.com/Nathan2go/]this site. Here you can find a few rough suggestions what is possible today without waiting for the future to happen.

MarsDog · 2004-06-27 13:39:07

The http://www.usatoday.com/tech/news/2004- … htm]design involves moving it around to dodge the satellites.
But how big a problem will be the lightning bolts ?

Rxke · 2004-06-27 13:40:55

mboeller... Ok. Nice idea.
I was at first *very* sceptical, the first page looks thrown together in half an hour, but then started to go through the links, hmmm...

Truly a 'we-can-do-this-today' tether-elevator.

Only... How 'easy' will it be in reality to dock?

a future 'SS2' going 90 miles instead of the 60-odd could reach it, but will it be able to connect.

(Back to read a lil' bit)

Thanks for pointing this out, mboeller!

PurduesUSAFguy · 2004-06-27 15:07:03

My biggest question is wether the technical challenges for developing a SSTO are any less then a space elevator. As far as the space elevator the only thing we need to develop is longer CNTs and matrix compound, both of which are progressing at a rapid pace for non-space applications.

SSTOs using chemical propulstion need to get a mass fraction of 90%. That means the development of ultra high strength composites. Plus you have to worry about developing a robust thermal protection system, and the entire propulsion problem. Personally I think that the space elevator is the best near(er) term solution to acess to space.

Don't get me wrong, I think the next 10-15 years will be dominated by heavy lift expendable/semi expendable boosters that will be used to implitment the first mission to Mars and a return to the moon (hopfully in that order).

Speaking off does anyone know what the constelation commision is finding on wether using and EELV or Shuttle derived launch vehicle? I think 100 tonnes to LEO needs to be the minimum baseline either way to keep on orbit assembly to a minimum. Does anyone have an estimate on what it would cost to revive the Energia?

ANTIcarrot. · 2004-06-28 04:01:38

SSTOs using chemical propulstion need to get a mass fraction of 90%. That means the development of ultra high strength composites. Plus you have to worry about developing a robust thermal protection system, and the entire propulsion problem. Personally I think that the space elevator is the best near(er) term solution to acess to space.

Or you apply high-school physics and use the square-cube rule. The shuttle ET weighs roughly thirty tons and carries roughly 650 tons of LH & LO. That's a mass ratio of around 20 with rather low tech materials. A vehicle re-entering with a large heat shield suffers less heating and needs less thermal protection per unit area than a smaller one. Make the heatshield large enough and you can use normal aluminium.

Of course congress has difficulty understanding complex scientific and engineering principles (like the square-cube rule) so don't hold your breath this happening any time soon.

As to the space elevator, I can't help but speculate what would happen if it turned out the only way to deploy it was from one continous 500ton piece from orbit. Wouldn't be dlightfully ironic if the ultra-heavy lift rocket was finally developed to launch the one cargo that would make it redundant overnight.

ANTIcarrot.

Rxke · 2004-06-28 04:25:24

About mboeller's 'small elevator' link...
Hmmm... Dreaming about BigelowAerospace, SpaceX and Scaled doing this together...

SpaceX to get the stuff in LEO, Bigelow for the Habs, Scaled for a Reusable suborbital passenger plane...

Their dreams are compatible (Except for SpaceX, it would eventually make their launchers obsolete...)

Now where's the fourth contributer: the one that builds the actual cable?

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#1 2004-06-26 17:12:34

Re: Space Elevator pilot program?

#2 2004-06-26 17:21:46

Re: Space Elevator pilot program?

#3 2004-06-27 01:40:16

Re: Space Elevator pilot program?

#4 2004-06-27 05:32:11

Re: Space Elevator pilot program?

#5 2004-06-27 06:11:36

Re: Space Elevator pilot program?

#6 2004-06-27 13:17:56

Re: Space Elevator pilot program?

#7 2004-06-27 13:39:07

Re: Space Elevator pilot program?

#8 2004-06-27 13:40:55

Re: Space Elevator pilot program?

#9 2004-06-27 15:07:03

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#10 2004-06-28 04:01:38

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#11 2004-06-28 04:25:24

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