(Harmon Everett) wrote in message . com...
(Alex Terrell) wrote in message . com...
I've proposed non rotating outer shells simply because of the mass
needed to stop radiation, and the fact that a non rotating, radiation
/ meteor shield can be made of cheap slag / by products.

OR cheap almost anything - or storage for bulk commodities, or waste
water treatment, or junkyard, all very good shielding for a
non-rotating outer shell. Easy to make, easy to maintain and very
useful!

I think it more economical to bring back entire NEOs. Then you have a
lot of waste sulphur and other fairly useless materials, as well as
all the Oxygen and Water storage.

Plus simle mass (solid or liquid) is effective as a meteor shield.


For a Cylinder structu

For transfer of people (and small cargos), I suggested a ring around
the axis, the interior of which would be a bit like a train. People
would enter from the gravity section, the ring would decelerate, and
people would exit on the other side. This has the advantage that
people don't have to travel to the axis, where there would be a lot of
congestion (especially as I propose one end of the axis as a light
pipe).

But the light pipe doesn't have to travel through the middle once it's
inside. Once inside, it can be directed anywhere without taking up
congested real estate, right?

Exactly: in the centre you have a complex mirror shape to direct the
light everywhere. This somewhat limits the max length of the colony,
but not too much.


For transfer of electricity, brush contacts could be used, or
potentially induction transfer, or motors and dynamos operating on the
circumference.

For transfer of data, I'd use wireless links running in small channels
(physical grooves, that are protected from interferenced with the next
groove). Each one would handle several Gbps of data packets.

For transfer of bulk cargos, a central airlock that would match spin
with the rotating section. This is a fail safe method of linking the
two. For a 500,000 person, 4km diameter cylinder this could be 25m
diameter, 100m long airlock.

Liquids and gases present the biggest problem, because the inner
section is pressurised and the outer section isn't (for the most
part). On the whole, water would be recycled within the rotating
section. However, for heat dissipation reasons, agriculture and CO2
breakdown would be done outside the main hab. Oxygen could be
reintroduced in a packaged liquid through the central airlock, which
would help with cooling.

CO2 would be solidified in giant radiators attached to the rotating
part (technical problem of shifting the CO2 and not blocking up the
radiators) and exported as dry ice to the farm areas, via the cetral
airlock.

A 500,000 people cylinder would need about 1,500 tons of 02, 750 tons
of food to come in per day, and 2,250 tons of CO2 to exit per day.

I'm working on a much smaller scale, about 125 persons, and a LEO
station 100 meters across. So you are thinking to export the CO2 to
the farms, and import O2 and food from the farms each day? I'm
thinking the agriculture will need to be integral to the living area.
Instead of hallways lined with filing cabinets, the hallways will be
lined with planter racks hooked up to the drip irrigation or
hydroponics tubes and fiber optic lights, and the harvesting and
maintenance would go on amidst the daily traffic. That still leaves
lots of agriculture that has to be done in its own area, but that
won't be open space particularly, either, as it will be done in
stacked racks allowing only as much vertical room as the
plants/aquaculture tanks/small animal pens need. I was counting on
growing algae as part of the sewage remediation, which would produce
O2 and animal feed. Would you export the sewage to the farms too?
Harmon

I'm beginning to think that two clylinders along the same axis might
be better. One for habitation, the other for agriculture. Then you
avoid all the rotation matching problems for you largest (by far)
import (food and Oxygen) and export (CO2 and waste). The second
(greenhouse) cylinder could actually be connected toruses - ligher
construction, and seperate, optimum climate in each.

I think for smaller scale there is less need to have linked living and
agricutural areas.