SMF Construction Process

> Yow! This is the expensive way - I had thought that space
> resources, by consensus, were the feed stock to run a SMF. As a
> 'hand-wave', I'll be able to accept this scenario (ignoring the
origin
> of the Stanford Torus sections)

No, I see I didn't make myself clear enough. I'm NOT saying build
the Stanford Torus by earth launch.

I'm talking about Heppenheimer's construction shack. Those first
2,000 workers have to live somewhere. It could be the barbell with a
sphere on top that Heppenheimer wrote about. I just chose to look
into the "small" torus option.

in order to address the "How do we
> assemble it" questions that follow; but I'd like to ask a few
questions
> of my own as well. Does this scenario assume an SPS already
exists?

No, this is the first effort to build up the infrastructure. The
housing, the refinery, the fabrication faciliteis, etc.

If
> so, what was it built out of, and how? If not, should an SPS be
built
> as a companion to a SMF to provide power and shading?

Yes, it should. In the future I'll start another thread where we can
discuss the minutae of bootstrapping up to a completed SMF, housing,
lunar facilities, etc.

What sort of
> resources will an SMF be built from, and how?

Earth launched because at the moment there are no lunar or orbital
resources to use, nor means to refine them, nor means to fabricate
anything. I'm premising this thread on that first step into orbit.

>
> >If this is done, then how much will we have to worry about vacuum
> >exposure in the open sections damaging all of the equipment.
> >
> Actually, I had always envisioned the construction of the
Torus
> being completed before moving any of the smaller equipment (and
> certainly furniture!) into it. This means that the equipment
could
> always be kept in a controlled (or at least pressurized)
environment.
> The larger pieces of equipment - which have to be built into the
Torus
> as it is initially constructed - will be made of hardier stuff,
and not
> suseptible to vacuum damage.

Yes, I see your point. I used to hold it myself, until I started
thinking about how expensive it is to keep an astronaut in space. I
don't think it'll be cost efficient to have the astronaut running
systems checks on all of the equipment, checking for bad wiring,
installing lightbulbs, moving in stoves, refrigerators, dishwashers,
computer screens, circuit breakers, etc. . . you get the picture.
Better to have that done by cheaper labor on earth.

I got to thinking about this problem and thought that a pressurized
assembly bay would do it better. As a bonus, the assembly bay can be
attached to the station and be used for construction of orbital
transfer vehicles, deep space probes, etc.
>
> >Should each section be pressure tight, then when sections are
> >joined, the pressure seals between them are cut out, so that the
> >many sections start to become a whole with the ends always capped.
> >
> Here you seem to be assuming that the sections will be
pressurized
> before they are assembled, but that may be problematic. Firstly,
you
> have to pay the launch cost for the atmosphere inside the
sections.

Workers need to breath! We either pay for it when we launch each
section, or we pay for it when we ship up atmospheric gas in bulk
after the station is completed. Where else are you going to get it
from? Not lunar oxygen because that whole mining/refining process
isn't operational yet. Not NEO nitrogen yet. I think it has to come
from earth, so that we can get those other processes started.

> Second, the 'Pressure Seals' will probably be hemispherical, or
at
> least domed to reduce the stresses on them and the edge of the
torus
> section where they attach - will your torus "tube" sections even
be able
> to touch each other? Or will you put an unpressurized ring
between each
> "tube" section, seal it in place over the end caps of two "tube"
> sections, and then remove the end caps?

I favor the latter suggestion because it gives us more usable volume.

If so, why not just build the
> majority of the station as unpressurized ring sections, only
joining
> them together and pressurizing them when you are ready?

Because I'm concerned about the vacuum damage to all of the internal
components.
>
> >What if the sections come in lateral halves or quarters, and we
> >can't pressure seal them off?
> >
> The sizes of all of the pieces here are really governed by the
sizes
> of the launch vehicles which up-port them. Here I'll hop back up
onto
> my soapbox to say that space resources sidestep this issue by
allowing
> the entire torus to be built as a single piece, and could provide
a much
> cheaper solution by eliminating much of the launch costs.

For a habitat, YES, of course. But if you mean the station, then who
will build it? Where will they live? What will they eat? Where will
they get air to breath? Where will the material come from? There's
nothing on the moon or orbit yet. This is the SMF and and housing
that I'm writing about. Have I misunderstood your point?

>
> >Should then, one of the first built structures in orbit be a
large
> >pressurized assembly bay (assembled piecemeal in a painstakingly
> >slow process to allow for the large open volume required) where
the
> >quarter sections are assembled, the ends sealed, moved out of the
> >bay and joined to other completed sections.
> >
> Here we are at the SMF again - should we build one, how, from
what,
> and what should it do? If we have one, how much do we really need
to
> launch? Where will the workers live? Myself I favor building a
SMF
> early on, but not first.

In my mind, the SMF and worker housing go hand in hand. I can't see
how you have one without the other. Perhaps you can lay out your
vision in more detail so that I can see how this can happen. Right
now, I see those first facilities being earth manufactured and then
additional capacity is added to them from lunar derived materials.

I tend to think that we need to build a
> prospecting facility (whether a lunar base or on-orbit NEO
retrieval
> center, I don't know or really care) and SPS first - mainly
because
> these are required for harvesting the available space resources.

Yes, I agree completely. But my question is dealing with the SMF and
housing.

Oh heck, why not . . . check out the new thread on bootstrapping,
right after this message.

Given
> the technology to build large bubbles of (flexible, inflated)
plastic in
> space, and to reinforce them with slender bands of sprayed on
aluminium
> (or maybe just more plastic - apparently metal has inferior
radiation
> sheilding properties), or mirror-coat them, on orbit construction
of
> these basic facilities should be easy.

Yes, you're right. We could launch big blocks of metal, plastic etc
and vaporize it over an inflatible sphere or cylinder. Then bring up
the airlock doors and then all of the internal ventilation
equipment, heating cooling equipment, etc.

Given an orbital assembly bay,
> should we bother pressurizing it? If you are building something
really
> big, and have to open the assembly bay up to let it out at the
end, how
> much atmosphere do you lose?

Depends on how efficient your vacuum pumps are. After you've
finished constructing your item, you depressureize the bay, open the
doors, send it out, bring in the new components, close the doors,
repressurize.

What happens with convection in the bay -
> will the welding create areas of superheated air which would be
> invisible hazards to the workers?

There will have to be superb air flow througout the bay so that
gases are dispersed. That's why I don't think the bay can just be
a "dumb chamber" a hollow shell. It'll need to be a finely
controlled environment.

What about frostbite - if the bay is
> sheilded, enclosed, and opaque, will it be unbearably cold once
you add
> an atmosphere to convect away the ambient heat?

Well, it's not a dumb chamber. It'll have environmental controls.

How will workers get
> around this huge volume, now that air restistance is a factor?

I envision ropes - one end tied to the bay wall, the other to the
structure being assembled. Now you have zero-g freedom of movement
about the structure, can use ropes for stabilizing the structure,
and for controlling your own motion.

If we do
> not pressurize the assembly bay, what advantages does it have over
open
> space, and how do we maximize those advantages?

Can't really see why there would be an assembly bay that wasn't
pressurized. In that case, don't build a bay.

With a bay, workers don't need to suit up, pre-breathe, limit their
time in space suit, can work without bulk of suit, have more ready
access to tools that they're familiar with and all of the sensitive
equipment in the station sections that are being asembled are
protected.

> >I'm just trying to imagine the asembly of a large facility for
> >thousands of initial workers and how we would step through that
> >process. Feel free to bring up your concerns and add to the ones
> >I've raised.
> >
> I am unconvinced that we will initially need thousands of
workers;

That's a whole other thread :) I'm just using Heppenheimer's figure
of 2,000+ workers in the construction shack scenario. And to me it
rings true considering how many specialized tasks there'll be in the
refining, fabrication, as well as facility and equipment maintenance.

> we may have to lift some fairly big and heavy equipment initially,
but
> dozens (perhaps a few hundred) workers should be able to handle
the
> building of the first, simple facilities. Even with thousands of
> workers, I am unconvinced that a Stanford Torus will be the first
> habitat.

I'm NOT writing about the Stanford Torus. The thread is entitled SMF
Construction process, and I never once wrote Stanford Torus :) You
can have a torus smaller than the Stanford study model.

Check out a graphic called "Torus sections" in the files section.

A simple 'Barbell' habitat seems much more likely to me,
> probably with a hub at the center of the bar for docking and
adding on
> of additional habitat sections. It has its own problems; but
built as a
> temporary lodging alongside of the essential initial orbital
facilities
> it could work well enough.

Yes, that's what I'm saying as well. A barbell station will also run
into most of the concerns I've raised in this thread. Barbell, samll
torus, small sphere, samll cylinder - it doesn't matter to me. It
needs to be built, it needs to come from earth, it needs to be
assembled in orbit, it'll have lots of sensitive equipment in it
that vacuum may damage. It'll have lot's on mundane stuff like
chairs, pillows, pots, pans, forks, lightbulbs as well. Any station
will have to house and support the workers, whether we're using your
figure of a hundred people, or Heppenheimer's (more accurately -
Alan Drigger of the Southern Research Institute who based his work
on earlier space station studies) 2,232 people.

Either way, that's a whole bunch more than 3 guys up in the ISS.

> Sorry - I seem to have added more concerns and questions than
> answers... I hope that some of this will help, and/or get the
creative
> juices flowing.

I enjoyed your response.