Space News Letter to Editor

--- In spacesettlers@yahoogroups.com, Al Globus wrote:
>
> On Friday, May 9, 2003, at 03:43 PM, victoriatangoman wrote:
>
> > With respect to delta-v disadvantage of the moon, with enough
volume
> > of material shipped, the implementation of mass driver technology
> > will arguably lower the costs of launch and erode the delta-v
> > disadvantage of the NEOs. This development further enhances the
Moon
> > as a "Just In Time" supplier of material that an NEO won't be
able
> > to match.
> >
> I am certainly no opponent of lunar mining.

I never inferred that your were. I'm just tryring to understand your
vision and short of you writing it out in detail, I'm relying on the
brief outline you wrote and your past writings.

So, my question becomes, how much material is returned from the NEO,
what is done with it in orbit, can the orbital infrastructure be
effective on a batch process rather than a continuous feed process,
and can the orbital infrastructure even be put in place in small
doses and with some components of an industrial process being
completely absent until future upgrades? Phew.

Let's say that you send up enough refining capacity to actually make
steel or aluminum. Further, you manage to return 1 ton, or even ten
tons of raw material to LEO. Can you achieve anything substantial
with a ton of refined steel and no fabrication facilities that'll
not be cheaper than just launching the finished product from Earth?

I'm having trouble seeing how the pieces come together in small
ways.

However, the mass drivers
> envisioned by O'Neill were very large. Multiple towers spread out
over
> kilometers.

First off. Is there a need for refined metal in orbit? If there is
then what will the market bear?

By way of analogy, there is need for copper in electrical wire. But
I'm uncomfortable spending a lot of capital on the whole mining and
refining process, so it's easier to just hunt for copper bearing
rocks and melt them individually to get the ore that I need.

Well, the sheer size of the mass-driver concept shouldn't disqualify
it if there is a market for the material it can launch. It may do
this more cost effectively than small NEO missions.

Further, a steady stream of material launched from the Moon may be
able to more efficiently feed a orbital industrial facility than a
sporadic and miniscule material stream from an NEO.

Rather than comparing small material streams from a NEO to the mass
driver streams, let's compare the mass of material that must be
launched from Earth to support an orbital industrial facility.

For the NEO scenario, one couldn't do with a single NEO retriever.
The scale is too large, and the material that is returned and
stockpiled would have to last years between return missions, thus it
is likely that multiple retrievers would be in service to reduce the
transport and stockpile issues. What is the mass of those NEO
retrivers.

Compare to the mass of the Earth essential components need to
complete a lunar mass driver. You wouldn't need to launch the
structural support needed for the mass driver. In Situ Resources
could be used to make lunacrete, etc.

Perhaps it is cheaper to send a small steel mill to the moon that
outputs the tower components and rails of the mass driver than to
launch those components from Earth.

The trick, IMHO, isn't to compare the economics of the NEO and the
Lunar missions in isolation, but to also factor in Earth-launched
provisions.

Thus, while the small amount of refined steel possible from a NEO
would cost less in the aggregate than a more capital intensive mass
driver, I'd venture the opinion that that same mass of steel could
be launched from Earth for substantially less than the cost of the
NEO mission.

So, volume of material needed in orbit will become a factor, and the
take-off point will be where the necessary capital costs of
developing orbital infrastructure can be amortized by the volume of
business and still compete effectively against Earth-launched
providers. I think that the smaller scale of NEO mining and its
uniform scaling costs in delevering more material to orbital
refineries will work against that model.

Although you get a lot of material once it's up and
> running, I'd be more comfortable with a development scheme that
could
> start returning useful material with a small investment and
> incrementally build with parallelism.

I just don't see how this is done. Can you provide more details on
the components needed and their utilization rates?

Retrieving small asteroids, or
> little bits of large ones, fits this better. Actually, the first
> asteroidal return mission just blasted off, and there are plans
for
> robotic lunar materials return.

Yes, and the Japanese are planning on returning with about a gram of
NEO material. Sounds like the "Aster-Ants" proposal :) Look at the
cost of the mission for the return of 1 gram. Not too promising.

TangoMan