From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Sun Mar 19 2000 - 06:08:09 MST
On Sat, 18 Mar 2000, Spike Jones wrote:
> > From: Spike Jones <spike66@ibm.net>, Thu, 16 Mar 2000
>
> > Do you have a plan to move Phobos' orbit?
>
> Ja, that thing's gotta go. Out. {8^D Amara I realize
> I am making light of a verrry difficult task,
Not really Spike. You should preface all of your discussions with
the assumptions wMNT or woMNT. Technically speaking, to be completely
accurate, you need "with" Self-Replicating Assemblers (wSRA) with a
relatively general "hard" (C/Si/Fe/Al) construction capability.
Those are likely doable with MEMS.
In my calculations for planetary dismantlement, I've used
highly conservative figures for solar collector areal mass
(1 kg/m^2). The disassembly times for the Moon, Phobos,
Deimos and Mars respectively are 67, 113, 109 and 175 days(!).
The moon wins because of its large area and greater insolation.
Phobos and Deimos have slow ramp times due to their small
surface area for collectors, Mars is handicapped by the
gravity well.
If you are more aggressive with your areal density, you
can push these times much faster. That has to be offset
by probable element limitations for the machines you need
to build. Until you get an engineering team together
to work out the element requirements for things like
the solar collectors and mass drivers, its difficult
to refine this any further. In addition I suspect
the composition of Phobos & Deimos is relatively
unclear (densities around 3.3 g/cm^3).
> but recall that the discussion started with theoretical strength
> calcs for an earth synchronous cable, and my contention
> is that with materials we have now, we are not there yet.
> With Mars, we might have materials that are just strong enough.
Spike, I think you should send a note to Landis if you have
questions about this. I've got his email address if you need it.
He has responded to my posts in the past.
>
> > Therefore, your tower in Mars synchronous orbits looks to me that it
> > is in a bit of danger from Phobos and its hypothetical ring.
>
> Ja. Well, maybe this whole notion really isnt a go. {8-[
> Damn. Unless we can figure out a way to clean up all
> that space dust. spike
You have to send out the MEMS cleaning bots to sweep it
off the solar collectors and bring it back as an additional
mass resource. :-] Or if its got any charge on it you
could use electrical field ram-scoop to funnel it into
your manufacutring plants.
R.
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