NEO Mining Question

>> The only limit will be in the mass driver, what is the
> maximum velocity it can launch.
> To some extent it might be possible to reduce the
> payload weight, increase the acceleration and thus
> achieve higher velocity. Again, the utlimate limit o
> nthe velocity the mass driver can achieve is a
> combination of the length and the switching speed of
> the SCRs.

Yes. Very good point. Thank you. Another variable that can be used
in the computation on whether to launch or not.

> > of the NEO comes back to a minimal point where it
> once again starts
> > to make economic sense to re-commence launching.

>
> The continuous stream does not need to come from a
> single asteroid, of course. It can be comprised of
> materials from multiple NEOs.

Absolutely. Have your crew take the equipment there once. Set it up
and let it run while the NEO is in optimum launch phase in its
orbit. Every once in a while send out a crew to effect repairs. Do
this for a number of NEO.

This whole scenario presupposes huge volumes of material. The
infrastructure isn't necessary if all you want is 1000 tonnes of
something. Better to do it with a rocket in that case. But 100,000
tons, maybe a 1,000,000 then it may be worth going this approach.

> I cannot imagine what such a thing could be. SPS and
> tourism are the only markets which have the potential
> for massive industrial expansion in space.

That's the point I made in my spacesettlers post "If we build it
will they come." Our thinking is constrained by our environment.
Who would have thought of radio or TV when a method for creating
vacuum was devised. What process, invention awaits us which is
tailor made for variable-g, hard radiation, no atmosphere
environment. How will our scientist's thinking change when that is
the environment that is only a few meters below their feet? When
they want to do an experiment in that environment, it'll be cheap
access, no jockeying for position for space launch. It'll be harder
for them to study the earth environment for up close, though their
high position should give them a different vantage point for
studying some earth phenomenom.

>
> > Then the only alternative is to get it into space
> and work to build
> > that market. I don't really know what that magic
> bullet wil be. It's
> > not SPS yet. Too much infrastructure required and
> there are
> > substitutes for SPS energy.
> >
> Yes. Although I would argue that costs of fossil
> fuels are artificially low. The price charged for
> fuel at the pump does not include the taxpayer cost of
> the US military, about $500 billion per year
> (includes DOD, DOE and VA), which is mostly to assure
> the security of our oil supplies - after all that is
> primarily what the war on terrorism is really about.
>
> And the present price of fossil fuels ignores the
> future cost of climate change and economic disruption.
>
> And the cost of nuclear power ignores the future
> cleanup cost of nuclear waste, and the additional
> military cost of keeping it safe from, terrorists.
>
> For a few per cent of the military budget we could
> develop SPS, and make the western world completely
> independent of islamic oil. That would change the
> global balance of power, and allow a considerably
> downsized military.
>
> > For isntance, come up with a cure for cancer vacine
> which must be
> > manufactured in a zero-g vacuum and requires a large
> infrastructure
> > in space and now you've got a solid footing to start
> space
> > industrialization. There is no substitute that can
> be manufactured
>
> I hardly think so. Vaccines are manufactured in
> quantities of a couple of tons per year.
> This needs little in the way of expanded
> infrastructure, such an operation could probably be
> housed within the existing ISS.
>
I was just using that as an example, not necessarily the BEST or
most likely example.

I agree with your analysis of the real costs of earth's energy
sources, but that analysis will not be adopted by any policy makers.

You know, the killer application may turn out to be militarization.
Not that I'm advocating it, but they have huge budgets, and if the
arms race or defensive positions develop in space, then an
infrastructure apart from NASA/scientific, develops, crew, experts,
followed by civilian support, followed by families, followed by
commerce.

It's a guessing game as to how the ladder will unfold. If energy
costs go through the roof because the greenhouse effect becomes so
severe that taxes are used to inhibit energy consumption, then SPS
has a good shot.

> > > >
> > > >
> > > > > solution I foresee is that downrange of the
> mass
> > > > driver is a
> > > > > particle beam cannon which applies the
> correct
> > > > amount of energy to
> > > > > the "in-flight" payload to alter its course.
> > > This
> > > > seems problematic,
> > > >
> > >
> > > I am not sure how that would work.
> > >

I'm not either. Vaporware. I was thinking it would work by having
the particle/energy beam vaporize some of the payload that was
arriving and these forces would work to slow down the velocity, or
change the orbit of the payload. Having a number of these beams
working on a payload and you could really fine tune its path and
velocity.

>
> Again, I am not sure how such a system wolod work.
>
> It might be most practical to attach a thruster or a
> mini-tug to every payload launched by the mass driver.
> This would permit in-course corrections.
>
> Note that launching from non-ideal orbital positions
> would not only result in higher launching velocity
> requirement, it would also result in hgiher braking
> velocity reequirement at the desitination.

Yes. Very good point.