Re: Space port/dock/ship yard location

On Aug 24, 2:11 pm, Space Cadet <kaw...@xxxxxxxxx> wrote:

If you wanted to build an orbit facility for interplanetary (or even
interstellar) craft
Where would you locate it?

Earth Moon L1?

Why? It's unstable and while it is closer to Earth than the L4 and L5
points, there isn't anything there.

Earth Sun L2?

The Earth-Sun L-points (all of them) are pretty well useless since as
of yet astronomers have found only dust there.

Some other location?

Depends on what kind of infrastructure is in place at the time and if
the craft is FTL what materials and processes are needed to create the
drive.

If you have a sizeable self-sufficient population of people (or
autonomous robots) in orbit then you'd want to work in-situ with the
materials you need to create the craft and if using humans a location
that provides needed resources to house and feed your workforce. If
you have no sizeable population of self-sufficient humans or
autonomous robots in orbit, then you are necessarily tied to the Earth-
Moon area.

The Earth-Moon L4 or L5 points are a good place to build a shipyard in
the near term since it is close enough that you could use non-
autonomous robots with tele-operation but are far more stable than the
other L-points. The moon is a great source of most of the basic
materials you would need to build the physical structure of a ship,
shipyard, and housing for workers. The moon can also provide reaction
mass in the form of water, at least in limited amounts. Getting
resources off the moon and up to the L-points can be done cheaply and
reliably via an electrical mass driver without the need of reaction
mass.

A less common and perhaps more interesting option are the Jupiter-Sun
L4 or L5 points. The points contain a large number of asteroids, more
like Kupier Belt Objects (Ice and Dust) than main belt asteroids
(silicates, carbon, oxides, and nickel-iron) however even KBOs are
likely to have some metals in them and the large amounts of volatiles
(gases, water, and organics) would more than make up for any
difficulty in having to dig to the centers of the objects to get at
any metals. Further, the Hilda asteroids (which are more like the main
belt asteroids) come fairly close to the Jupiter-Sun L4 and L5 points
(actually enter them in some cases) which would seem to indicate that
at least some main belt asteroids may have been captured in the
Jupiter-Sun L-points. If you are going to make a ship a small 1km
radius nickel-iron asteroid is all you need and more. A story based
reason for making an interstellar vessel so far from the Earth would
be that the FTL drive was so experimental that the possibility that it
could cause major havoc could not be ruled out, so putting it far away
from the home world would be a good idea. If you aren't making a FTL
vessel, the copious amount of reaction mass available in the area
would be an excellent reason to build it there.

The main asteroid belt has many similar advantages, but is also a more
common location than the Jupiter Trojans.

Another less common location to build a shipyard might be the Mercury-
Sun L2 point. Using polar mining operations on Mercury to harvest
heavy elements for a SFinal FTL drive that might not be available
elsewhere in sufficient quantities. Though you would probably need to
do some hand waving to make Mercury a more inviting spot than the main
asteroid belt.
.