NEO Mining Question

>

>
> We're still crossing wires here. Why 100kg of
material to launch 1
> kg payload? What I'm prosposing is payload launched
by electrical
> energy alone. We don't need the 100kg mass at all.
Just lots of
> energy. Think of how the larnar mass-drivers are
proposed to
> function. No lunar mass is used for propellant.
That's exactly what
> I'm proposing.
>

OK

> Consider that the lunar mass driver will be
launching payloads at an
> escape velocity of 3000 m/s. Some NEO's will require
an optimum
> delta-v considerably less than that. As launching
progesses beyond

It might need either more or less velocity depending
on the asteroid's orbit and its position versus the
optimum launch window.

> the optimum window, the delta-v will continually
increase. At some
> point in the orbit of that NEO, the energy expended
(KE=m*V2) will
> be so great that it'll make sense to cease launching
until the orbit

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.

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

If the velocity required exceeds the velocity
capability of the mass driver, then there is no point
in launching anything until the conditions improve.

> You know, in order to facilitate a continuous stream
of payloads
> arriving at the Manufacturing Facility, we might
consider payload

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

>
> Personally, I think the breakthrough will come when
there is a
> technology, service, process that CANNOT be done on
earth, where the
> substitution effect doesn't apply and where
prfitable demand exists.

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.

> 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.

> > >
> > > > 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.
> >

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.