RE: [FT] Debris Reef Harbour [LONG]

Remember that in space, distance is nothing if you have the time.  If
you're willing to wait years, then shoving a gigantic mass at relatively
slow speeds will get it there with a minimum of energy at either end,
since there is very little if any loss of velocity while traveling - so
while a commercial tug may be limited to pulling a few megatons across
the system in a a couple of hours/days, it may be able to shove a
gigaton on a slow trajectory  across system that takes months or years
to arrive.

Just look at all the space probes - the vast percentage of the energy
used for space probes is to get them out of Earth's gravity, but once in
space, they can gain velocity using gravity slings.  They are then
unpowered for the rest of their flight to Saturn, Jupiter etc.	At the
far end, a small deceleration burst (30 minutes or so) puts them into
the proper orbit. It takes years (sometimes almost a decade) but they
get there eventually.

After all, a prime sci-fi ideal is that you shove entire asteroids to
where you want to process them.  So instead of going out to the asteroid
field and building a refinery, you shove (small - 5-10 km) asteroids
towards the spot in the system where you want the eventual harbor,
capture them and then process them.  If the processing plant is the
center of the location of where you want the debris, then transportation
after refining is essentially nil.  You could schedule asteroids to
arrive "just in time" for the refinery, although your "pipeline" might
be years long depending on how cheap you were and how far the asteroids
were from the site.

Economy of bulk is very important, as it is today - shipping in giant
containers thousands of miles across the ocean is cheaper than
transporting the same bulk over the same distance in separate trucks. 
It takes longer with ships, but is much cheaper per ton/mile.  You just
need to be able to afford the time it takes.

--Binhan

-----Original Message-----
From: Doug Evans [mailto:devans@nebraska.edu]
Sent: Thursday, October 21, 2004 7:21 AM
To: gzg-l@csua.berkeley.edu
Subject: Re: [FT] Debris Reef Harbour [LONG]

>A Debris Reef Harbour will usually be encountered in systems that
border
>potentially hostile intersellar nations...
>
>Systems that are home to a nation's reserve fleet...
>
>And systems that enjoy extensive asteroid mining operations.

Not sure if your intending that it has to be 'all of the above', but I
would, as it seems to me that it would take a heck of a lot of
transport,
as in prohibitive, to move that much material any appreciable distance.
Remember, in reality, you're talking about a sphere, though the spirals
are
in two dimensions.

In fact, if the mining process wasn't geared to launching trailings to
be
concentrated in the staging area, even the vast distances that actually
occur in asteriod fields as we know them would probably be prohibitive.

Sorry, I'm always a little suspicious of an idea that sounds like
something
for nothing... ;->=

However, the mechanism sounds fascinating; I'll have to find an
appropriate
pop can to give it a try!

The_Beast