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RE: starship-design: AsterAnts



> I have this vague memory that a lot of the water they use on shuttle
> flights is produced as by the fuel cells they use to generate
> power.  So
> in a sense they may be getting their water for free; the
> money was spent
> on launching the fuel.
>
> Note that the per-pound launch costs quoted for payload are typically
> calculated by dividing the cost of flying an entire shuttle mission by
> the weight of the payload.  Water carried for crew use _isn't_ payload
> and therefore won't have much effect on the payload launch cost.
>
> The cost per pound to put the entire shuttle in orbit is quite a bit
> less than the payload launch cost; the payload is only a
> fraction of the
> entire shuttle weight.


This is all true, but the fact remains that there is a cost for the water.
Even though it is a byproduct, the hydrazine costs something and the fuel to
launch the hydrazine still costs something. If it wasn't for this fortuitous
circumstance, they WOULD have to launch water regularly.

If one is going to assume an increased presence of people in orbit, then
water will become an issue. The SSTS will not provide enough for a full ISS
crew complement (if we ever get there). The AsterAnts concept is assuming
that on orbit manufacturing will happen, and therefore there will be more
people up there, so we will need not only materials for the manufacturing
operations, but also water for the people. In this respect, water was
actually considered almost a byproduct of the mining operation. (Here we go
again, we are getting something for free... .)

To reiterate and expand upon the reason I posted the concept in the first
place, an Explorer class ship will need materials such as fuel when it
reaches its' destination. It isn't practical to send out (or carry) lots of
big mining ships, but if we had AsterAnts bringing lots of small rocks back
to a central site for processing, that makes a lot more sense. We get
metals, fuel, and even water, from an autonomous craft that doesn't even
consume any fuel itself. Pretty slick.

Lee