Heat management, recycling, $, and space ores

andy-nimmo wrote:

> Hi Ian,
>
> Forget the diamond, concentrate on the nanotubes. They are about to
> begin to become a mass production probability for many reasons apart
> from space elevators, but when that happens, the cost of dropping a
> space elevator from geosynch will also drop. Chances are that in 50
> years time it will be very economic to build an elevator - just about
> the time space mining will also become a fairly major economic
> industry.

I've done a fair amount of carbon nanotube research for NASA (see
http://www.nas.nasa.gov/Groups/Nanotechnology/publications/1997/applications/
and http://www.nas.nasa.gov/~globus/papers/NanoSpace1999/paper.html).
Last I looked, the longest carbon nanotube ropes were about 1/2 mm,
which is very long for a molecule. Thus, we need to scale the length by
about 7 orders of magnitude to make an orbital tower. Ropes are
believed to contain continuous carbon nanotubes, but that has not been
proven. Weaving carbon nanotube may be difficult because Van der Walls
forces between the tubes are quite weak. It may be possible to
functionalize the nanotubes with other molecules so they bind with each
other, but getting the functional groups in between tubes in an
individual rope may be very difficult.

Finally, recent results suggest that carbon nanotubes are not as strong
as we once thought. I haven't looked at this material in much depth
though as I'm not doing carbon nanotube research anymore.

>
> The space tourist wallahs are already forecasting seriously that there
> will be jobs in space hotels for between 20,000 and 100,000 hotel
> staff within as little as 30 years. That is quite a lot of folk living
> in space - and that isn't counting the 5 million space tourists a year
> that they expect by 2030.

Without a cheap reliable launch vehicle, this is just talk.
Unfortunately.

>
> One of the problems is that the scientific fraternity are liable to
> oppose the tourists, so there is already resistance in high places
> where governments still tend to consult scientists rather than tour
> operators on matters of space.

Scientists, like most everyone else, will follow the money. Consider
contacting your elected representatives and voicing your views.

Al Globus
aglobus@..., (650) 604-4404
http://www.nas.nasa.gov/~globus/home.html

The dinosaurs weren't spacefaring. We are. I don't think that's an
accident.
Maybe we are life's taxi to the stars.

I think we should:

1. Devote half of NASA's budget ($7 billion) to reaching NASA's 2020
goal of
reducing launch costs to Low-Earth-Orbit to $220/kg with a 0.01% failure
rate.
This should enable space tourism. The resulting orbital hotels will need
to
develop efficient orbital life support and other necessary technologies.

2. Build orbital space colonies. The materials in the largest asteroid
are
sufficient for orbital colonies with a combined surface area about 500
times
greater than Earth's. Eros alone could make over ten thousand space
colonies,
each with about about 10 square kilometers of 1g living area.

3. After a few generations of orbital living, people won't need their
colony
to be near Sol. Then small groups of colonies with populations in the
tens-of-thousands can set out on multi-decade journeys to nearby stars.

Except the launch goals, none of this is even a little bit official.