[meteorite-list] Phoenix Analyzing Martian Soil Data

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue, 5 Aug 2008 03:02:49 -0500
Message-ID: <01d801c8f6d1$a8382a30$4c25e146_at_ATARIENGINE>

Hi, Darren, Doug, List,

    There is no doubt that Mars was made for a
Space Elevator, or is it the other way around?
Arthur C. Clarke's novel "The Fountains of
Paradise" details the much easier reqirements for
a Mars Elevator, over the terrestrial difficulties.

    The Space Elevator or Orbital Tower has been
invented over and over again, independently, by a
number of people during the 20th century: Tsiolkovski
in 1895, Isaacs (and Vine, Bradner and Bachus)
in the 1966, and Artsutanov in 1960 before them
(but unnoticed in the West). In 1975 Jerome
Pearson thought of and worked out the full math
of the Elevator without knowing that anyone else
had ever done it, another independent invention.
And even Clarke himself "invented" it. It's one of
the "most-invented" ideas in engineering!

    As for the need for Unobtainium, we do not
require so expensive a material. We can make do
with Almost-there-ium. It requires 65 gigaPascals
(with no safety margin) and carbon nanotubes
are in the 52 to 63 gigaPascal range.

    There is a great Wikipedia article on Elevators:
http://en.wikipedia.org/wiki/Space_elavator

    There is a (struggling) Space Elevator company:
the Liftport Group:
http://en.wikipedia.org/wiki/LiftPort_Group

You can read a portion of the Liftport Group's
book about Space Elevators at Google Books:
http://books.google.com/books?hl=en&id=nvTRoXs_V30C&dq=liftport&printsec=frontcover&source=web&ots=hROXoK54uc&sig=99jRmKrn6la7JvkhD0Zx3kALpT0&sa=X&oi=book_result&resnum=10&ct=result#PPA11,M1

The viewable portion of the book contains
Arthur C. Clarke's 1981 paper on the Elevator.
It has a very interesting section on the question
of materials. Did you know there is a design
("the stepped tower") that could be built from
ANY material, no matter how weak? Paper,
for example.

    However, it appears that composite ribbons
of bonded carbon nanotubes are very close to
the strength required and can be improved to
meet the need. That's what the Liftport Group
proposes using, anyway. Here's an old (2006)
video of a 1000-foot climb by a Liftport lifter:
http://www.youtube.com/watch?v=QjcaQT_ssE4

    There are other endeavors also: Black Line
Ascension (nice video, anyway):
http://www.blacklineascension.com/

    There's a Foundation with a demonstration
prize, the Spaceward Foundation:
http://www.spaceward.org/

    There is no invention more likely to actually
happen than the one that only depends on a slight
progressive improvement in materials. Present-day
composite ribbons of bonded carbon nanotubes
are over half the needed strength, and that is a
technology that is just beginning. We'll get there,
if not with them, with some engineered material.

    My $0.02 worth.



Sterling K. Webb
----------------------------------------------------------------
----- Original Message -----
From: "Darren Garrison" <cynapse at charter.net>
To: <Meteorite-list at meteoritecentral.com>
Sent: Tuesday, August 05, 2008 1:04 AM
Subject: Re: [meteorite-list] Phoenix Analyzing Martian Soil Data


On Tue, 05 Aug 2008 01:54:09 -0400, you wrote:

>Not to mention having most of the material needed to manufacture rocket
>fuel in situ (just add the iron or better yet aluminum shavings) to get
>the heck out when necessary.

Hm. That makes me think... if we ever make it to Mars and decide to stay a
while, maybe a skyhook would be possible. I have my doubts that the right
type
of unobtanium will ever be found on Earth to make one practical/feasible
here,
but with the much lower gravity for Mars, a geostationary orbit half as
high,
and less wind to worry about, it might be more doable.
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Received on Tue 05 Aug 2008 04:02:49 AM PDT