On Nov 19, 2009, at 4:50 PM, Andrew Crystall 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
Question: Would you need to go the asteroid belt for this, or are
there inner-system asteroids, or even NEA's in easy-to-capture
orbits, which would be useable?
There are definitely inner system and near-Earth asteroids. Not sure
how many of them are nickel-iron in large enough quantities to invest
in trying to catch one -- about 10% of asteroids are M-type, and I
can't seem to find any info on whether that population distribution is
the same for the near-Earth variety as it is for the main-belt variety.
The NEA's are in fairly elliptical orbits with perihelia much lower
than that of Earth (which would be great for PV-assisted VASIMR, which
could lower the aphelion to the point where the asteroid was exposed
to near Earth-level solar illumination and allow raising the
perihelion as well), so it would take a long time and a lot of
reaction mass to get into a transfer orbit that would put a capture
within reach of a high efficiency engine. Unless a translunar
slingshot would help. ;) About the only thing we'd have going in our
favor is that most of them aren't too much out of the plane of the
ecliptic, so at least there wouldn't be huge plane changes involved.
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