Redesigning O Neill cylinders

On Jan 10, 2005, at 12:08 PM, Costea Andrei wrote:

>
> The biggest disadvantage of the sphere is producing only a small strip
> of habitable land at the expensive of a gargantuan volume. Another
> disadvantage of the sphere shape is that it can be very hard
> compartmented and administered.
>

It is also rotationally unstable. I.e., you must actively maintain the
axis of rotation.
>
> The cylinder has a very large living area but a very important
> disadvantage is the psychological one, because it is very unusual too
> see persons up your head.

This is easily solved by adding smaller cylinders in the middle (see
Lewis One,
http://alglobus.net/NASAwork/papers/RNR-91-018/RNR-91-018.html). These
cylinders
also provide very large amounts of low-g surface for non-polluting
industry, agriculture, recreation, storage, etc.

> Another disadvantage is the too large amount of material used to
> create the necessary radius for the pseudogravity creation.

Actually, the shielding required for a cylinder is the smallest of all
shapes (per unit 1g living area).

> Rotating cylinders also require too much atmosphere, of which 78%
> needed to be shipped up from earth in the form of nitrogen.

The atmosphere is a tiny fraction of the mass of a colony. Nitrogen is
probably available in Near Earth Asteroids (although not on the Moon).

In a late 2004 talk, Rutan made the following predictions:

1) Within 5 years 3,000 tourists will have been to space.
2) Within 15 years sub-orbital tourism will be affordable, and 50,000
people will have flown.
3) Within 15 years the first, expensive orbital tourist flights will
have happened.
4) Within 25 years orbital tourism will be affordable.

There have been a lot of wild claims in this business, but Rutan may
know what he's talking about. His privately financed SpaceShip One was
piloted into space three times in 2004, and Rutan has a contract with
Virgin Galactic to build a true sub-orbital tourist vehicle.

Al Globus
Evolvable Systems Group (http://ic.arc.nasa.gov/projects/esg)
CSC at NASA Ames Research Center
http://www.nas.nasa.gov/~globus/home.html

Views expressed in this email are only my opinions and are not the
position of any organization I'm familiar with.