[AR] Zero g and radiation was Are 1,000 Starships adequate to live on Mars?
- From: Keith Henson <hkeithhenson@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sat, 2 Jan 2021 11:17:03 -0800
roxanna Mason <rocketmaster.ken@xxxxxxxxx> wrote:
Everyone keeps putting the rocket in front of the horse, no one has figured
out how to mitigate the radiation and zero g problems, no one!
That's almost true. I spent ten years looking into the engineering
and economics of power satellites. Finally, reach the point where the
cost of power on the ground would undercut coal, though not hydro. (3
cents per kWh, $12 B
per 5 GW power satellite, including the rectenna at a billion dollars.
Started working on a shielded 50-meter spinning habitat for a minimal
number of workers. It was not hard to do, a little faster rotation
than NASA likes, 6 rpm. Then I got the galactic cosmic radiation down
with 6 meters of non-spinning polyethylene. (You can't build them in
LEO and self-power out to GEO because of the space junk. If you go
above the junk, you get into the edge of the lower Van Allen belt
where the radiation is rapidly fatal.)
Unfortunately, that broke the economic model for the startup cost
because it took 60,000 tons of polyethylene or about the mass of two
power satellites before you could put workers in space.
Huge disappointment because a lot of my motivation, clear back to the
L% Society days, was to get people living in space.
It's still possible using robots or teleoperation. If they can dance,
https://youtu.be/fn3KWM1kuAw
they are dexterous enough to build power satellites.
But you are dead-on correct that not enough attention has been paid to
zero-g, or reduced g, or radiation. I now think humans will have to
wait till the robots build us spinning, shielded habitats. Or,
post-singularity, we load up on cell repair machines to repair the
radiation damage as it happens.
Keith
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