From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Wed Oct 23 2002 - 18:08:27 MDT
On Tue, 22 Oct 2002, spike66 wrote:
> Assume you
> decide to grind up part of the asteroid to use
> as reaction mass to accelerate the remaining part.
Fine. Even if I reduce a 5m asteroid to a 2m asteroid
if I can capture it in a controlled orbit it has
transformed itself from a hazardous mass in space
to a useful mass in space.
> It is a tradeoff, depending on how much energy is
> available and how much mass you decide to throw away.
Yes, I understand this and clearly at the current time you
have perhaps 3 choices (a) our existing ion thrusters;
(b) our existing LH2 LOX engines; (c) our existing LOX
and kerosene engines. I believe the Zubrin Mars refueling
scheme was based on an as yet untested (or at least not
commonly used) fuel.
If its a hazard you don't care how much mass you have to
consume to deflect it (witness the Rafal/Eugene discussions
on whether nuclear weapons would be effective in deflection).
I'm interested in using semi-hazardous masses as a test suite
to produce useful deflection strategies and at the same time
turn the semi-hazardous masses into something useful for
space development.
What I am interested in here is whether we currently have
the means to turn hazardous mass into useful mass? As far
as I can tell that requires knowing how much delta-v needs
to be applied to the object (including derotating it if
that is currently the situation in which it is in) and
then getting it into an orbit that allows the Earth-Moon
to capture it.
It shouldn't be too difficult to apply our current
capabilities (of ion/rocket engines) to determine the
limits of the mass of objects in relatively similar
objects that we can put into useful orbits.
Its fine to be concerned with the brakes on your motorcycle
Spike. But you have to balance that with the possible fate
of humanity. We are currently still Earth-bound. The sooner
we permanently eliminate that situation the more secure the
future of humanity will be.
Robert
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