Re: More Space Elevator news

From: Frank Scrooby (X_at_Xer.com)
Date: 06/30/04 

Date: Wed, 30 Jun 2004 09:30:31 +0200

Hi all

"Richard Lamb" <n6228l@earthlink.net> wrote in message
news:40E22CDF.2E2D8C5E@earthlink.net...
> Ian! Et Tu?
>
> I've read you and Jorg for quite a while now, and you guys
> have always had an excellent command of the scientific stuff.
>
> Sure, I understand the idea that centrifugal force is holding
> the thing 'up'. That is NOT what I'm questioning.
>
> While the mass is very small compared to the mass of the earth,
> the arm (length) is huge compared to the diameter of the earth.
>
> I can't work out the numbers because I have no way to even
> fantasize what the mass might be.
>
> Anybody want to posit a Scientific Wild Assed Guess as to the
> mass involved?

According to one PDF (NIAC_Space_elevator_report.pdf) I have on the subject
a 100,000 km elevator mass would have a mass of approximately of 750,000 kg.
That is 7.5 kilograms per kilometer of cable. (I think the PDF came from
http://www.niac.usra.edu/studies/ but I could be wrong). That is the
finished product. It is assembled slowly one strand at a time, with an
initial cable capable of supporting only a 425 kilograms payload.

The finished cable would have a 20 ton load capacity, and be able to launch
such a payload every 4 days. Assuming some down time, and 10% repair mission
per year that is 324 tons of payload a year or just over two years to build
another elevator.

By comparison in terms of tonnage the mass of the WTC debris is supposed to
be in the order of 55,000 tons or 55,000,000 kilograms (quoting from memory,
feel free to correct me if I'm wrong). Human beings routinely throw up
structures in the same order of magnitude of mass as the space elevator and
just routinely throw them down again (deliberately through demolition or
undeliberately through bad construction, earthquake or other disaster).

Commercial fiber spin plants (cotton and other fibers) routinely turn out
720,000 kilograms per year, and individual machines (gins) process as much
as 20,000 kilograms in a day. (Again quoting the PDF). Ok, so carbon
nanotubes are not cotton, but spinning them will be a similiar technology.

Another pdf (Space_Elevator_finalreport.pdf) available at the same site has
a very

>
> Richard Lamb

Regards
Frank Scrooby

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