Another Space Elevator Concept

[Kayra]

Originally Posted by Pyrotex

Even though the centripedal force is opposite and equal to gravity at Geosynch, .

I always get Centripedal and Centrifugal force confused.

Isn't it Centrifugal that counters gravity (with is the centripedal force in this case).

Please, no giggling if I have this backwards again.

[Pyrotex]

Originally Posted by Kayra

...I was trying to say that the increase in weight you mentioned might not occur at the rate you specified, which might allow for a cable of a single width to be used. If a single width cable capable of supporting itself and cargo can not be used then the entire concept of a conveyor belt system ( I like the anology) will not work...)

Okay!
Well, then I see no reason why your idea won't work. The cable would have to be thick enough so that every piece of the loop would be strong enough to support the entire loop from Geosynch (plus the elevator).
We can assume somehow that we find a way to bend the loop over the "pulleys" or their equivalents.
Solar power at Geosynch could keep the pully in operation.
I guess my only criticism is that it has moving parts. Wear and tear, you know.

[Kayra]

Originally Posted by Pyrotex

We can assume somehow that we find a way to bend the loop over the "pulleys" or their equivalents.
Solar power at Geosynch could keep the pully in operation.
I guess my only criticism is that it has moving parts. Wear and tear, you know.

I think most current designs have this as a ribbon rather then a cable. Increasing width rather then girth. That should help with the flexability issue.

Moving parts BAD.. I agree.
I started thinking about the entire concept because of the complexity and number of moving parts in the climbers. That and the extensive ground support (powerfull laser) required to run the device.

Would this design not greatly simplified the overall system?

[Buffy]

Design is always the easy part: its building it that gets interesting. Cost? Its prolly *much* cheaper in the short run to keep boosting tin cans with unstable chemicals. Now if you had a requirement to get something into orbit on a *daily* basis, you might have an excuse for all that up-front investment.

Cost-benefit-analysis,
Buffy

[Pyrotex]

Originally Posted by Kayra

...Isn't it Centrifugal that counters gravity (with is the centripedal force in this case). Please, no giggling if I have this backwards again.

[Ahem!]
Sorry, I was giggling at somebody else on a different thread.

Everybody gets these messed up. Technically, there is just ONE force, the Centripedal force, which pulls OUTWARD due to the rotation of the system. The so-called centrifugal force is the tension on the radial element (the cable) caused by the pull OUTWARD. In other words, the cable has to "pull" in a kind of metaphor to keep itself in place. But this isn't a new force at all. It's the tension caused by the Centripedal, which IS a new force.

The metaphor is a human swinging a rope with a bucket attached to the end. The bucket experiences a REAL force that pulls it outward in the circle due to its rotary motion. The rope keeps the bucket from flying off. The centrifugal force is the tension that the rope "experiences" by preventing the bucket from flying off. The tension is REAL--it could break the rope. But the only "real" FORCE that is created in the metaphor is the one pulling OUTWARD on the bucket. The Centripedal.

Errr... I may have gotten the words reversed, too. I'll have to look them up.

[Kayra]

Good point

4 billion annual income from current satellite launches should help Cost-benefit-analysis along nicely, and it is only that low due to the small number of launches each year. Give them more access, and more will come.

The first group to create such a device should be able to get their investment back VERY quickly, as the only competition is VERY costly. They could undercut them by 30%, make a MASSIVE margin, and recoup investment in short order.

[Kayra]

Originally Posted by Pyrotex

[Ahem!]
Sorry, I was giggling at somebody else on a different thread.

Everybody gets these messed up. Technically, there is just ONE force, the Centripedal force, which pulls OUTWARD due to the rotation of the system. The so-called centrifugal force is the tension on the radial element (the cable) caused by the pull OUTWARD. In other words, the cable has to "pull" in a kind of metaphor to keep itself in place. But this isn't a new force at all. It's the tension caused by the Centripedal, which IS a new force.

The metaphor is a human swinging a rope with a bucket attached to the end. The bucket experiences a REAL force that pulls it outward in the circle due to its rotary motion. The rope keeps the bucket from flying off. The centrifugal force is the tension that the rope "experiences" by preventing the bucket from flying off. The tension is REAL--it could break the rope. But the only "real" FORCE that is created in the metaphor is the one pulling OUTWARD on the bucket. The Centripedal.

Errr... I may have gotten the words reversed, too. I'll have to look them up.

Thanks Pyrotex. that helps
Lets see how many more giggles I can give you ...

[Buffy]

Originally Posted by Kayra

The first group to create such a device should be able to get their investment back VERY quickly, as the only competition is VERY costly. They could undercut them by 30%, make a MASSIVE margin, and recoup investment in short order.

Remember to go back to your spreadsheets, take your absolute worst case cost and multiply by 4 to account for underestimated construction schedules and by another factor of 4 for Rummy's "unknown unknowns". Now recompute. Oh and don't forget to add additional huge amounts for the construction R&D, and the two failures that will occur because somebody forgot something.

Murphy was right,
Buffy

[Kayra]

Originally Posted by Buffy

Remember to go back to your spreadsheets, take your absolute worst case cost and multiply by 4 to account for underestimated construction schedules and by another factor of 4 for Rummy's "unknown unknowns". Now recompute. Oh and don't forget to add additional huge amounts for the construction R&D, and the two failures that will occur because somebody forgot something.

Murphy was right,
Buffy

Ouch. that is a lot of "Factors" I understand the necessity of such when dealing with the "first of".

If I had any concept of the projects estimated costs I could try to make a business case. Unfortunately, I don't.

Would this help the case at all? If I were an owner of such a magical device, and actually got it running. (those overruns were murder), I would try to circumvent my future competition by helping them. (eventually)

Offer to loft a cable for them.. 3 conditions apply. They can not aid anyone else in lofting one, you are granted license to any improvements they may come up with, and you get a reasonable amount of royalties. Repeat for all competitors with sufficient funds until demand can meet market requirements.

Even if (after the first couple years of operation) you never lifted anything other then other tethers, and used the entire capacity for power transmission, you should be able to recoup your costs in a reasonable time frame.. no?

[Buffy]

Originally Posted by Kayra

Would this help the case at all? ...I would try to circumvent my future competition by helping them....Offer to loft a cable for them.. 3 conditions apply....Even if (after the first couple years of operation) you never lifted anything other then other tethers, and used the entire capacity for power transmission, you should be able to recoup your costs in a reasonable time frame.. no?

That's a completely rational business plan *structurally*, but the devil is always in the details... The question is, how long can you keep your invested capital tied up in this for the amount of time that it will take to build up demand by your competitors, and can you *really* be sure you can get them to agree to pay royalties that match your investment. Donno. I'd be sure to patent something in the process, or else someone with bigger funds and a longer time scale will duplicate your plan and simply be able to price you out of business.

Even with a patent of course, you run into the 17 year curse, where your competitors invest in building up their solutions and suppressing demand until your patent runs out...

Projections beyond 5 years are always pure conjecture....

Grounded,
Buffy