Date: Wed, 04 May 2005 08:42:57 -0400
From: "Paul Haggerty" <Paul.Haggerty at noaa.gov>
To: WSFA members <WSFAlist at WSFA.org>
Subject: [WSFA] Re: Bring a lunch for this elevator ride...
Reply-To: WSFA members <WSFAlist at WSFA.org>

Mike B. wrote:

>At 01:05 PM 5/3/05 -0400, Paul Haggerty wrote:
>
>>Mike B. wrote:
>>
>>>That's amazing.  I didn't know they were so close to actually building a
>>>beanstalk.  I hope this doesn't turn out to be a scam.
>>>
>>For more information on space applications of tethers check out:
>>http://www.tethers.com/
>>
>
>Beanstalks and tethers are two different ideas.  They rely on similar
>technological advances (really strong cables), but the physics and use
>methods are different.
>
<snip>

>-- Mike B.
>
True enough, but that's not the reason I posted the link.  Unfortunately
I was in a bit of a rush and didn't have time to say more.

The reason for the link is that the Tethers Unlimited group have been
working on the problem for quite some time.  Yes, the technology for
building the nanotubes for the beanstalk will be different, but both
beanstalks and tethers actually share many things in common.  The main
one I wanted to point out was resistance to severing.  A single strand
runs the extreme risk of being severed by space debris. And the longer
spent in LEO, the greater the risk.   The classic proposal  to avoid
this is to increase the diameter of your tether (or beanstalk), but this
adds enormously to the weight.  TUI has another solution:
http://www.tethers.com/Hoytether.html

The same kind of principle can be applied to the beanstalk to increase
its reliability and longevity.

And of course the rest of the site is just filled with cool applications
for tethers that I would love to see put into practice as well.

Paul

--

Paul Haggerty
Science and Technology Corporation
NESDIS/NOAA
Phone: 301-457-5258 x142
E-mail: Paul.Haggerty at noaa.gov