NEO Mining Question

I agree with your basic conclusions about asteroid mining and
incremental shipping.

I would add stockpiling of materials and manufactured goods probably
at lunar L5 as needed (or IF needed).

Generally, if it works on earth you can be pretty damn well sure it's
going to work in space. You factor in zero-G as possible or create
the G-forces needed via spin systems. Mining.. melting.. casting..
are nothing odd or peculiar. If there's any uncertainty, experiments
(and evidence gathering) can be done in space (ISS or other
platform). But, generally, most anything you can do on earth can be
done MORE EASILY in space. And if you're really hard up for that
gravity thing - no big deal.

George

--- In spacesettlers@y..., "victoriatangoman"
> I see two classes of feasible scenario for mining NEA. I would
> appreciate people's feedback on which they think is most plausible
> and any flaws in logic, physics or engineering that I've made.
Also,
> I don't consider it feasible to move an entire asteroid. The
kinetic
> energy required for a mass of that huge size is mind moggling.
>
> The first scenario is to send out a mining ship, process the
> material and either send the ship and material back, or keep the
> mining facility there doing its mining and refining, while the ship
> heads back to earth-space.
>
> The second scenario is one that I'm leaning in favor of. Send out a
> ship with a mining facility, seeds of a mass driver and the seeds
of
> a power facility. Establish the facility, extract the material
> needed to construct the main mass of the mass driver and the solar
> power facility, integrate the earth-manufactured parts for these
> devices, and then commence shipments to earth-space. After a while,
> the crew departs back for earth.
>
> Obviously, this second proposal is more complex. I envision a small
> solar furnace, extracting the bulk materials required for the
> manufacture of the systems. This shouldn't be too complex. It
> wouldn't need to capture gases, so minimal storage would be
> required. It has only one mission: process enough steel, etc to get
> the system functional. The rest of the mined material will be
> refined in earth-space.
>
> So, here are my technical concerns. Can a mining/excavating system
> run autonomously? I'm envisioning a territory is staked out and the
> excavating units are bounded within that territory. They excavate
> under some AI heuristic, head back to the processing center,
release
> their load into the mass driver processing unit, then head back to
> mine more material. The dropped off material is weighed to a
> standard mass, an orbit is computed, a variable velocity of launch
> is applied.
>
> So, how complex a system do you think we can leave unattended with
> present day techology? I guess this question applies to self-repair
> capabilities. I don't know the state of the art in this engineering
> field. Can anyone help? No future guesswork please. I can imagine
> things too, but for now, I don't really know what is capable.
>
> Another problem is if the the mass driver is attached to the NEO
> then as the NEO progresses in its orbit the mass driver will become
> oriented in the wrong direction to fire a payload to earth-space. A
> 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,
> but I'm not sure. Or the mass driver can be pivotable. So it is off
> of the NEO and the payload is sent to it on conveyor belt. The mass
> driver is oriented to allow the payload to achieve proper orbit.
But
> how do we mitigate the forces of the payload launch which are
acting
> against the point of attachment between the mass driver and the
> NEO? Perhaps we don't attach the mass driver to the NEO. The
> payloads are lobbed up to the mass driver but we'd still be left
> with the mass driver changing its postion relative to the NEO. So
it
> would need some propellant to bring it back into position. I tend
to
> favor the mass driver being off of the NEO, because now the
launches
> aren't confined to the plane of the NEO. But I'm still left with a
> lot of feasability questions. I'd very much appreciate people's
> thoughts on the specifics of making such a scheme work.
>
> Now when the payloads are appraoching earth-space, the question
> becomes how much has the course varied over the weeks, months, or
> years of transit? I've seen reference to a lunar mass driver being
> able to hit a target within 10+ meters. But over the course of tens
> of millions of kilometers, the error may grow to a 100+ kilometers,
> so, now what? If the particle beam guidance system works, then how
> about a series of accelerators stationed around the perimeter of
the
> 100 km zone of error. The propellant needed to keep these
> accelerators on station should be relatively easy to provide
> considering their proximity to earth-space. Radar guidance could
> establish the trajectory of the incoming payload, and the
correcting
> force vectors can be applied from any number of the accelerators.
At
> the same time they could be applying energy to slow the payload's
> velocity. The payload is thus guided to a mass catcher and taken to
> the Materials Processing Facility. Is this achievable? Or is this
> science fiction at the present? I know we don't have this equipment
> now, but is the technology there yet?
>
> I'm really drawn to the efficiency of mass driver propulsion
> compared to the inefficiency of rocket propulsion but I see it as
> really pushing our technological limits. How much of what I've
> proposed is within out means, and how much am I way off base on?
>
> One last thought, I'd rather send the NEO material to earth
> incrementally, rather than moving the whole mass of the asteroid,
> consuming its mass for propulsion and not seeing the material reach
> earth for many years. At least this way material is reaching earth
> incrementally, even though it creates all sorts of guidance
problems.