starship-design: Manufacturing Infrastructure

["L. Parker" <lparker@cacaphony.net>]

> -----Original Message-----
> From: KellySt@aol.com [mailto:KellySt@aol.com]
> Sent: Saturday, April 22, 2000 8:55 PM
> To: lparker@cacaphony.net; KellySt@aol.com;
> starship-design@lists.uoregon.edu
> Subject: Re: starship-design: FTL travel
>
>
>
> In a message dated 4/21/00 9:58:43 PM, lparker@cacaphony.net writes:
>
> >You still missed the point, if you are only building one of
> the end product,
> >it doesn't matter if you prefab it in sections and boost it
> or boost it
> >all
> >at once.
>
> Well actually if you launch it in peaces its much more likely
> to work right,
> and not leak!

I wasn't arguing the technical superiority or lack thereof, just the
economics of mass production. As a mater of fact, in today's industry, QA is
rather much of an after thought instead of an integral part of the
manufacturing process. A purpose built unit which is one of a kind and built
basically by hand will almost always be superior in quality.

However, once the kinks have been worked out of a manufacturing process, the
_overall_ quality will be superior to the hand built unit because errors
won't be repeated at random.

> >However, if you have an industry that is mass producing engines for
> >instance, it will be cheaper to use several of those engines
> if necessary
> >rather than building one special purpose engine to do the same job.
>
> Probably true, course that assumes your starship can use off
> the shelf
> engines.

True, but let's look at a typical case. Rotary Rocket has a design for a
MUCH better engine than any currently existing. However, due to time and
budget constraints it made more sense to use the FasTRAC engine developed by
NASA, which although better than existing engines, is still not as good as
the one envisioned by Rotary Rocket.

It is adequate for their needs, available now, and CHEAPER. Most of those
cost savings are because the FasTRAC engine is as close as it gets to a mass
produced engine.

> >It
> >will
> >be cheaper still if those engines are all being mass
> produced in orbit
> >from
> >materials which are already in orbit rather than boosting ANY of the
> >components from Earth.
>
> Thats a big asumption.  No reason to think a space built
> peace of equipment
> would be cheaper, likely to be more expensive.  Smaller
> market and far
> greater expenses for the space based manufacturing equipment
> and personel.

Well, since we haven't actually built ANYTHING in orbit, it is kind of hard
to issue a blanket statement that it will be cheaper. I was basing that on
several economic issues that are known - the cost of lifting raw materials
or even not so raw ones out of Earth's gravity well chiefly. I was also
assuming that the comparison was being made after the manufacturing facility
was built.

If we ignore the cost of the infrastructures of both groundside and
space-borne facilities for the moment and simply compare the cost of the
materials and delivery costs, it is FAR cheaper to obtain the materials in
orbit than it is to deliver them to orbit. So much so that some economists
are worrying already about what will happen to global market prices for
precious metals when asteroid extraction gets into full gear.

> >Yes, the infrastructure IS expensive. I stated that right up
> front. But
> >it
> >is also paying it's own way. So the cost is amortized across
> other projects
> >besides just one interstellar craft.
>
> Are you sure its paying its way?  Unless there are a lot of
> projects, you
> could be costing more.

Read the Commercial Space Transportation Study. It is all laid out and
totaled up. Yes it would pay its own way, but even then it still requires
that launch costs drop to $100/pound to LEO, and that is just for people and
consumables!

> I was refuring to reusables, obviously there can't be any
> significant cost
> savings with expendables!

Sorry, but you were unclear...at least we agree!

> For those kinds of reductions, you need enough market to keep
> fleets of such
> vehicals very busy.  You are after all talking about reducing
> cost to orbit
> to costs simlar to trans ocean air frieght.  That takes similar sized
> markets, or radically improved tech.  Some ae on the books,
> but you need
> massive launch requirements to run them at efficent enough rates.

Also pointed out in the Commercial Space Transportation Study. And as Ben
and Curtis figured out for themselves, it is a Catch-22 situation. We must
have the industry in space to create sufficient demand for launchers to
bring the cost down to the $100-$200/pound range, but the cost has to come
down to that range first in order to make the industry possible!

>
> >> Now obviously your not going to want to lift millions to
> >> hundreds of millions
> >> of tons for a big starship if you could get it cheaper in
> >> space.  But you
> >> wouldn't want to life a thousand ton steel mill to make 40
> >> tons of steel.
> >
> >Which is why I said LOTS of orbital industry paying it own
> way doing other
> >things. The steel for the interstellar probe becomes just
> one more job,
> >not
> >THE job.
>
> Ok, then you need a market large enough to keep those
> facilities that busy.

Which brings me back to where all of this started, the optimum way to make a
starship is in a space-borne shipyard that is making lots of ships with lots
of experience in making all those ships, with lots of off-the-shelf
components with proven life expectancies, etc. A situation that will only
arise when there are several thousand to several hundred thousand people
living and working in space to create that much demand in the first place!

> Nice list, but it doesn't alter the major problem.  What can
> you sell to
> earth in enough volumn to pay for the operation of the platforms.

If I knew the answer to that one, I would be very busy drumming up investors
right now! I and lots of other people have studied this for years, and
besides the catch already mentioned there are others. At the moment asteroid
mining seems to be the only thing with real potential. Tourism is a dirty
word to investors and all of the Space Access companies are careful to avoid
using it when they talk to potential investors. I can't say I agree, but
that seems to be the reality of it. Commercial communications has been the
big driving force in launchers so far, but it really doesn't require the
kind of presence needed, just launchers. There are lots of possibilities and
most are detailed in the Commercial Space Transportation Study.


Lee

"Space isn't remote at all.  It's only an hour's drive away if your car
could go straight upwards." - Sir Fred Hoyle