On Nov 19, 2009, at 1:16 PM, Alberto Monteiro wrote:
Bruce Bostwick wrote:
That being said, what I really wish someone would propose is sending
a robot propulsion/navigation system out to a conveniently sized
nickel/ iron asteroid, bring it home, and park it in an orbit high
enough to keep it from decaying for the foreseeable future
Great idea! All it would require was a propulsion system
that does not waste fuel to change the asteroid's speed from
about 50 km/s to 30 km/s in the perihelium of the transfer orbit,
and it would be cheaper than launching stuff from Earth at
the enormous 10 km/s speed (give or take a few km/s).
Alberto Monteiro
Not as tall an order as it might sound, using something like VASIMR
which has an Isp of up to 5000 s. Once you get out of the atmosphere,
a higher efficiency engine system can spread out the delta-V across a
fairly large period of time, and with enough engines and enough energy
(some of which, for part of the mission at least, can come from PV
panels), I think it would be within reach to bring us a suitable size
asteroid.
And as far as how much could be mined from one, well ..
http://en.wikipedia.org/wiki/Asteroid_mining
The asteroid 16 Psyche is believed to contain 1.7×1019 kg of nickel-
iron, which could supply the 2004 world production requirement for
several million years. A small portion of the extracted material
would also contain precious metals.
I think it might be worth a try. ;)
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