One Small Step

It is necessary that the device can manufacture to a spec (it doesn't
need to understand the design, just to be able to make it), but it is
not sufficient. It needs to also be able to make its own basic
building blocks.

True, but I feel we may be getting into philosophy here. What do we
mean by "understand". I was simply using the word to mean a
translatability. We have CAD. The computer can recognise assemblies and
parts, and put 2 sub-assemblies/parts into the correct orientation
relative to each other. That is all that I mean here by "understand".

Having said that, alot of stuff that is easy in principle would be
expensive to actually do.

Well, that depends on how you go about it. To me the CRITICAL "small
step", is getting a robot to build from a CAD/CAM specification.

wrote:
True, but I feel we may be getting into philosophy here. What do we
mean by "understand". I was simply using the word to mean a
translatability. We have CAD. The computer can recognise assemblies and
parts, and put 2 sub-assemblies/parts into the correct orientation
relative to each other. That is all that I mean here by "understand".


Ahh, ok, I was worried you meant strong AI or something.

Having said that, alot of stuff that is easy in principle would be
expensive to actually do.

Well, that depends on how you go about it. To me the CRITICAL "small
step", is getting a robot to build from a CAD/CAM specification.

There are a few examples of that already ... very simple though. For
example:

http://ccsl.mae.cornell.edu/research/selfrep/
and
http://staff.bath.ac.uk/ensab/replicator/

The first one is IMO simple. All that happens is that a tower of
blocks picks up blocks and builds another tower. It only works if the
pieces are in exactly the correct position. However, more
fundamentally, it only works with custom made blocks.

For the system to be effective, it needs to be able to make the basic
blocks themselves from raw materials. I think that those blocks could
probably be programmed to make a table if there were enough blocks and
it had enough "squares" to draw power from. Each block contains a
microprocessor, so they can probably form a parallel CPU.

Actually, what they do that is really cool is arrange the blocks into a
spring. I was wondering how you could attach legs to body so that they
were flexible. OTOH, I don't think the system allows wheels to be
easily made.

However, it is not very useful from a self replication point of view
unless the blocks can be made from raw materials. Each one of those
blocks contains a small motor, an electromagnet and a microprocessor.
This would make them pretty hard to make. They also need an external
electric power supply. Perhaps the set of blocks needed would be lots
of those blocks and then also a few custom blocks with cutting tools
etc. The microprocessor is the killer. That would need to be made out
of transistors or something ... photolithography would be to hard.
OTOH, maybe the microprocessors could be shipped in.

Mike Combs wrote:
wrote in message
oups.com...

In the space colonization literature of the seventies, a mass
driver would launch twenty or so kilograms at a time

You might be looking at the earlier studies (the ones involving soil-filled
sacks made from fiberglass). The later studies recommended launching small
spheres of lunar soil which had been sintered at the focus of a solar
mirror. They were described as being about the size of a softball, so I
would expect them to come closer to weighing one kilogram than twenty.

One of the advantages of making a proposal that turns out to be
misguided is that it is sure to generate some traffic in the form of a
sensible reply. using a 'sack' to deliver lunar samples intact might
still be sensible if the first market for moon rocks is for keepsakes.
It would not pay for the program but it could give some return on
investment long before the infrastructure for processing is in place.

to be collected by
a 'catcher' that would intercept it prior to perigee, otherwise it
would crash back into the moon.

This makes it sound like you're visualizing the catcher orbiting the moon.
The catcher was stationed at the L-2 point behind the moon.

It's all comming back to me now.

This shows the payload trajectory: http://ssi.org/assets/images/Ch08p150.gif
Earth is towards the left in this illustration.

Perhaps a much smaller system could be
built to launch 'cannisters' that would have not only the coils for
acceleration, but a pressurized oxygen tank with a nozzel in front,
along with valves on the sides for attitude control. At apogee a jet
of oxygen would raise the perigee so that the cannisters could be
collected at leasure.

You're esentially proposing replacing a dumb payload with a smart one
capable of self-propulsion and navigation. I don't see any reason to assume
that the latter could be made smaller than the former (or more economical,
for that matter).

Point taken.
--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

wrote in message
ups.com...

One of the advantages of making a proposal that turns out to be
misguided is that it is sure to generate some traffic in the form of a
sensible reply. using a 'sack' to deliver lunar samples intact might
still be sensible if the first market for moon rocks is for keepsakes.
It would not pay for the program but it could give some return on
investment long before the infrastructure for processing is in place.

I'd have to allow that "Sintered Moon Spheres" probably wouldn't be as
marketable as "Genuine Moon Rocks".

I've always imagined that the fiberglass sacks were replaced by the sintered
spheres because the processing of the latter was less complicated and
expensive than the fiberglass factory for the moon.

This makes it sound like you're visualizing the catcher orbiting the
moon.
The catcher was stationed at the L-2 point behind the moon.

It's all comming back to me now.

No biggie. There are lots of people who are confused on this issue.


--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

Mike Combs wrote:
wrote in message
ups.com...

One of the advantages of making a proposal that turns out to be
misguided is that it is sure to generate some traffic in the form of a
sensible reply. using a 'sack' to deliver lunar samples intact might
still be sensible if the first market for moon rocks is for keepsakes.
It would not pay for the program but it could give some return on
investment long before the infrastructure for processing is in place.

I'd have to allow that "Sintered Moon Spheres" probably wouldn't be as
marketable as "Genuine Moon Rocks".

I've always imagined that the fiberglass sacks were replaced by the sintered
spheres because the processing of the latter was less complicated and
expensive than the fiberglass factory for the moon.

This makes it sound like you're visualizing the catcher orbiting the
moon.
The catcher was stationed at the L-2 point behind the moon.

It's all comming back to me now.

No biggie. There are lots of people who are confused on this issue.


--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn


There was a news story a couple of days ago that some moonrocks were
stolen from the car of a NASA instructor in Virgina Beach. The story
claimed that they were worth ten times their weight in high quality
diamonds.
Given that the mass driver is about the simplest component of a space
processing program and that moon rocks have a plausable market 'as is',
maybe the driver should be the most immediate goal. While sintered
hollow balls may make the best use of available resources, the fact
that the 'bag' will only be a few percent of the mass of its contents,
it might make more sense to import these from earth for the first few
years of operation.

wrote in message
oups.com...

Given that the mass driver is about the simplest component of a space
processing program and that moon rocks have a plausable market 'as is',
maybe the driver should be the most immediate goal. While sintered
hollow balls may make the best use of available resources, the fact
that the 'bag' will only be a few percent of the mass of its contents,
it might make more sense to import these from earth for the first few
years of operation.

Sure, given that the moon rocks market is probably going to be a lot smaller
on a pound for pound basis (dumping too much on the market would depress the
price).

The notion of the fiberglass sacks was in support of space construction
programs which might involve tens of millions of tons of materials
processing.

So: one might start out with only the lunar mass driver, L-1 catcher (only
one would do), and some modest STS that could get the rocks back down to
Earth. Sell moon rocks in the short term, and only ramp up with an orbital
ore refinery and orbital manufacturing center at a later point.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

Mike Combs wrote:
wrote in message
oups.com...

Given that the mass driver is about the simplest component of a space
processing program and that moon rocks have a plausable market 'as is',
maybe the driver should be the most immediate goal. While sintered
hollow balls may make the best use of available resources, the fact
that the 'bag' will only be a few percent of the mass of its contents,
it might make more sense to import these from earth for the first few
years of operation.

Sure, given that the moon rocks market is probably going to be a lot smaller
on a pound for pound basis (dumping too much on the market would depress the
price).

The notion of the fiberglass sacks was in support of space construction
programs which might involve tens of millions of tons of materials
processing.

So: one might start out with only the lunar mass driver, L-1 catcher (only
one would do), and some modest STS that could get the rocks back down to
Earth. Sell moon rocks in the short term, and only ramp up with an orbital
ore refinery and orbital manufacturing center at a later point.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn

While Apollo moon rocks will likely keep their value, the first ton of
lunar gravel will likely depress the price to that of rare meteorites.
Those with a martian origin go for about $300/gm. Perhaps the sole
selling point will be surface impact melting, moon rocks would keep
their ET origin visibly intact.
I came across the claim that a mass driver could be carried by a single
shuttle but did not realize that it was ONeil that said it. What is
the ratio between the weight of the 'egun' to the payloads it propells;
30000/1?
Perhaps the system could be scaled down to launch 'bag bolts' smaller
than a golf ball. Fifty gm/min during the lunar day would add up to
ten tons/year.

I looked in to some of the chemistry, and tried to "design" a lunar
chemical works, which you can see he

http://fp.alexterrell.plus.com/web/C...stellation.pdf
(under Phase 3, Expansion of Lunar Equator Base)

This uses hydrogen reduction as a first step, followed by a number of
other processes. An alternative is to:
- React everything with Fluorine to liberate the oxygen
- React the fluorides with potassium to liberate the elements, and give
KF
- Electrolyse the KF to recycle the K and F.

Alex Terrell wrote:
I looked in to some of the chemistry, and tried to "design" a lunar
chemical works, which you can see he

http://fp.alexterrell.plus.com/web/C...stellation.pdf
(under Phase 3, Expansion of Lunar Equator Base)

This uses hydrogen reduction as a first step, followed by a number of
other processes. An alternative is to:
- React everything with Fluorine to liberate the oxygen
- React the fluorides with potassium to liberate the elements, and give
KF
- Electrolyse the KF to recycle the K and F.

I wasn't able to call up your site. Do you have any cost estimates?
What would be the mass of the equipment for a given mass of output?

wrote in message
oups.com...

While Apollo moon rocks will likely keep their value, the first ton of
lunar gravel will likely depress the price to that of rare meteorites.

You're probably right. Sure would have been nice to have a terraced
approach to High Frontier, though.

I came across the claim that a mass driver could be carried by a single
shuttle but did not realize that it was ONeil that said it.

Just bear in mind that this comparison considers the PV panels powering the
mass driver to be a separate component. That would actually have several
times the mass.

What is
the ratio between the weight of the 'egun' to the payloads it propells;
30000/1?
Perhaps the system could be scaled down to launch 'bag bolts' smaller
than a golf ball. Fifty gm/min during the lunar day would add up to
ten tons/year.

A smaller bore mass driver would certainly be a smaller upfront investment
(what I keep telling people who talk in terms of mass drivers to launch
big-ass oxygen tanks or finished components of various types). But I was
initially attracted to the proposed idea with the notion of the system later
getting used for large scale construction in HEO. 10 tons per year would be
too small to support things like SPS.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn