Slashdot | Small Asteroid Making 400,000 Mile Pass By Earth
Paul D. Fernhout
"Universe Today is reporting that a small 10m asteroid, discovered earlier
this month and named 2009 BD, is passing within 400,000 miles of Earth.
Although the asteroid poses no threat to the planet, the site reports that
the asteroid is still very interesting, as it may be a rare co-orbital
asteroid (as in, shares the same orbit as Earth)."
That's about 30ft X 30ft X 30ft of material, or about 27000 cubic ft. A
cubic foot of sand is about 100 lbs, or about the weight of a person. So,
that asteroid has the mass of about 27000 people.
I'm going to do some speculation here, maybe it will be wrong, but I'll put
it out as a hypothetical argument. You might expect that an achievable life
support system for zero gravity life might only mass a few orders of
magnitude more than the person it supports (a nanotech one might mass less
than a person) with really efficient recycling. So, ignoring radiation
shielding (done electrically? or by improved biotech resistance to
radiation?), and assuming a diversity of elements there, and assuming
support mass of about 1000 times the weight of a person, I'm guessing that's
maybe enough mass to build a habitat for maybe 30 people indefinitely with
technology we might hope to build. With nanotech, that's maybe enough mass
for a habitat of thousands of people.
But, that's a very small asteroid. Bigger asteroids may support many more
times bigger communities.
Now, the figures above are just wild guesses and deliberatively provocative.
What would be interesting is to make or find ones that were accurate and
based on detailed analysis. For Island One design, or Bernal Sphere,
http://en.wikipedia.org/wiki/Bernal_sphere
http://sketchup.google.com/3dwarehouse/details?mid=c7a8a5a0b23e4b95f43a8a1e423488b7
that might support 20,000 people. One estimate of the mass required is:
http://space.mike-combs.com/spacsetl.htm
4,000,000 tons, or about 200 tons per person, or 400,000 lbs, or about 4000
times the weight of a person per person. Of course, there is an economy of
scale there perhaps. Anyway, so my ballpark estimate above to support 30
people on that small asteroid are not that out of the realm of possibility
(ignoring radiation shielding or that the balance of elements might be
wrong). If you could get that ratio improved by a factor of ten, then you
could support a small village of 300 with that much mass. Perhaps each
person might were a spacesuit that was like a second-skin, in which case if
you don't need to pressurize the habitat, it could effectively be miles and
miles in size, with just a little mass here and there for hints of
structure, or it might have holographic structures for aesthetic appeal, and
so on. Speculating wildly, with nanotech giving you a real invisible second
skin, you could have a small city of about 300000 people from the mass of
that asteroid (assuming a support mass of only one tenth the mass of a
person per person).
Anyway, that's all why I think in the long term, if technology advances,
Mars really isn't that interesting except as tourism. There goes a city's
worth of mass if you had advanced technology, flying right by Earth. And
that is a small asteroid.
Anyway, I know this is all speculative -- I'm just pushing the limits of the
life support ideas here. Bucky Fuller had suggested if we really understood
design science it would not take more than a small amount of mass to make a
space suit that could support a human life in the cosmos indefinitely.
--Paul Fernhout