A Moon base is too far; an asteroid ship better alternative:)
Bounty
neat idea and was on the right track with his "Celestial Titanic" ship:
http://uk.geocities.com/aa_spaceagent/restricted/earth-ring.html
Just look at all these squillions of $$$ benefits:
-Save billions of dollars in ferrying up parts from Earth to build the
large-scale outer framework
-Save thousands of man hours and hundreds of radiation-exposed
astronaut spacewalks for station assembly
-Asteroid surface offers strong commercial potential for mining
precious minerals
-Bulk of the project from in-situ excavation, transportation of
asteroid to high Earth orbit and some initial mining, performed
robotically. Human crews arrive near the end to "seal the entrance" and
establish colony
-Opportunity to experiment re-creating a "miniature Earth" with
gravity, biosphere and self-sustaining ecosystem within a natural,
rocky structure much like Earth's own crust
-Logistically more attractive for easier access from the ground than
either a base on the Moon or one established on Mars
-First "truly promising", permanent off-Earth colony potential within
decades!
-Potentially a full-function transportation vessel for sailing the
great interplanetary or even interstellar oceans of space...
Why oh why do I want to go all the way to that grey thing, when there's
more economical business to be done nearer home with the right rock
from outer space? This is a smart idea - was a smart idea... still
plain wishful thinking.
Bounty
Rodney Kelp
to the moon and process it. Plus drilling and mining on the moon may
discover all kinds of useful minerals and possibly water.
We could do it if we only spent what is spent on cosmetics and cosmetic
surgery which is a total waist of money on vanity.
"Bounty" <boun...@lycos.com> wrote in message
news:1107269912.0...@c13g2000cwb.googlegroups.com...
Joe Strout
"Bounty" <boun...@lycos.com> wrote:
> Why oh why do I want to go all the way to that grey thing, when there's
> more economical business to be done nearer home with the right rock
> from outer space? This is a smart idea - was a smart idea... still
> plain wishful thinking.
Rocks closer to Earth than the Moon are extremely rare. And when we see
one, we call it a "near miss."
Now, in terms of delta-V, there are some which are relatively cheap to
reach, though those too are pretty rare, and close encounters are even
rarer. So you'd be looking at extremely long trip times, unless you
have a very big rocket with lots of fuel to waste.
The Moon is the natural place to start for offworld development because
it is easier to reach than any other place except Earth orbit, pretty
much no matter how you look at it.
,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| j...@strout.net http://www.macwebdir.com |
`------------------------------------------------------------------'
Hop David
Bounty wrote:
> Okay shoot me down if you have to but I think that "Ahad" guy had a
> neat idea and was on the right track with his "Celestial Titanic" ship:
>
> http://uk.geocities.com/aa_spaceagent/restricted/earth-ring.html
In situ exploitation of asteroid or comet resources have been proposed
by science fiction writers and bona fide scientists. For example David
Brin (who is an sf writer and has been a planetary scientist) was a
co-author of "Heart of the Comet".
Giving himself pretentious sounding names (AA Institute of Space Science
& Technology) and presenting stuff that's been around for awhile as his
own revolutionary ideas doesn't enhance Abdul's credibility.
He needs to look at some of the problems. Launch windows to and from any
specific asteroid occur much more seldom than Lunar launch windows
(although there are asteroids whose windows occur about as frequently as
Martian windows).
Capturing an asteroid to earth orbit is difficult. There's a substantial
amount of delta vee and even a small asteroid can be quite massive.
There are varying hazards depending on the capture scheme. And I would
guess that no matter how safe the plan, there will be political obstacles.
This scheme:
http://www.cnn.com/2004/TECH/space/05/19/asteroid.eater/
proposes using an asteroid's own material as reaction mass.
This could make altering an asteroid's path more doable. But Madmen
aren't off-the-shelf technology SFAIK.
I like Abdul's enthusiasm. But I wish he'd calm down and make more
sober, substantial contributions.
--
Hop David
http://clowder.net/hop/index.html
Joann Evans
>
> Well if you had a moon base you could go and fetch an asteroid and bring it
> to the moon and process it.
Why necessairily the Moon? You can't land it, any 'processing' will be
on the asteroid itself, so it might as well be a high Earth orbit.
And 'go and fetch an asteroid' is easy to say...
> Plus drilling and mining on the moon may
> discover all kinds of useful minerals and possibly water.
> We could do it if we only spent what is spent on cosmetics and cosmetic
> surgery which is a total waist of money on vanity.
And what's wrong with vanity?
--
You know what to remove, to reply....
Mike Combs
news:mZSdnctIcfA...@adelphia.com...
> Well if you had a moon base you could go and fetch an asteroid and bring
it
> to the moon and process it.
Are you processing the asteroid into products for use on the lunar surface?
Because if the products are intended for use anywhere else, better to
process the asteroidal material in orbit than on the lunar surface.
--
Regards,
Mike Combs
----------------------------------------------------------------------
Member of the National Non-sequitur Society. We may not make
much sense, but we do like pizza.
Malcolm Street
> Why oh why do I want to go all the way to that grey thing, when there's
> more economical business to be done nearer home with the right rock
> from outer space? This is a smart idea - was a smart idea... still
> plain wishful thinking.
>
All you need to do is get a dinosaur-killer-sized asteroid into orbit closer
than the moon without risking it hitting the earth. Funnily enough, I
think a lot of people mightn't like that idea.
Good luck being allowed to do it even without technical obstacles.
I think asteroids in the longer term have a major role to play in space
exploration and colonisation, but FFS keep 'em away from the earth! :-)
--
Malcolm Street
Canberra, Australia
The nation's capital
Fred J. McCall
:Rodney Kelp wrote:
:>
:> Well if you had a moon base you could go and fetch an asteroid and bring it
:> to the moon and process it.
:
: Why necessairily the Moon? You can't land it, any 'processing' will be
:on the asteroid itself, so it might as well be a high Earth orbit.
Except most of our industrial processes work better in the presence of
at least some gravity. It makes a lot of things a lot more
convenient.
I'd think you just chuck it into a crater from on high and then go
strip mine it out. No 'landing it' necessary. Little to no
atmosphere means you can use solar furnaces for smelting.
: And 'go and fetch an asteroid' is easy to say...
Yep.
:> Plus drilling and mining on the moon may
:> discover all kinds of useful minerals and possibly water.
:> We could do it if we only spent what is spent on cosmetics and cosmetic
:> surgery which is a total waist of money on vanity.
:
: And what's wrong with vanity?
Rodney talks like someone who has never seen his girlfriend without
makeup. :-)
--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
Big Show
first. Those 3 are the stepping stones without much doubt but in which
order do they come for us? I wish somebody could weigh up the pros and
cons and map out a 100 year plan with computation. I think the dude's
phrase: "The destiny of our species rests on the simple toss of a
coin..." is rather apt. Well done Mr. Ahad for a thought provoking
article!
Joann Evans
>
> Joann Evans <bon...@frontiernet.net> wrote:
>
> :Rodney Kelp wrote:
> :>
> :> Well if you had a moon base you could go and fetch an asteroid and bring it
> :> to the moon and process it.
> :
> : Why necessairily the Moon? You can't land it, any 'processing' will be
> :on the asteroid itself, so it might as well be a high Earth orbit.
>
> Except most of our industrial processes work better in the presence of
> at least some gravity. It makes a lot of things a lot more
> convenient.
>
> I'd think you just chuck it into a crater from on high and then go
> strip mine it out. No 'landing it' necessary. Little to no
> atmosphere means you can use solar furnaces for smelting.
But could you make the impact as a velocity low enough to leave
something worth working on (as opposed to scattering much of the mass
over half the Moon, and ejected back into space, with the following
orbital debris issues), as well as no major damage to the area?
That's what I meant by 'can't land it.' You can certainly arrange an
impact, but...
Kent Paul Dolan
> All you need to do is get a dinosaur-killer-sized
> asteroid into orbit closer than the moon without
> risking it hitting the earth.
No, and no. You don't have to start with something
10 km in diameter, 200 m in diameter is a huge good
start for just getting a lot of mass available that
isn't at the bottom of (quite so deep) a gravitational
well, and you don't have to get it physically closer
than the material on the moons surface, just
energetically closer, which any stable Lagrangian
point orbit would suffice to accomplish.
Now that Smart-1 has proved humankind capable of doing
space the slow and steady way, what _are_ the
implications for robotically shipping a "rock" from
the asteroid belt to L5, probably (I have no clue how
to do the math) simpler than diverting something in a
profoundly non-circular solar orbit, like an earth's
orbit transiting asteroid, if one is willing to be
patient.
And, what constitutes a big enough "rock" to be worth
the effort?
xanthian.
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
alext...@yahoo.com
Kent Paul Dolan wrote:
> "Malcolm Street" <mst...@internode.on.net> wrote:
>
> > All you need to do is get a dinosaur-killer-sized
> > asteroid into orbit closer than the moon without
> > risking it hitting the earth.
>
> No, and no. You don't have to start with something
> 10 km in diameter, 200 m in diameter is a huge good
> start for just getting a lot of mass available that
> isn't at the bottom of (quite so deep) a gravitational
> well, and you don't have to get it physically closer
> than the material on the moons surface, just
> energetically closer, which any stable Lagrangian
> point orbit would suffice to accomplish.
>
a first attempt, go for about 20m diameter - about 8,000 tons.
> Now that Smart-1 has proved humankind capable of doing
> space the slow and steady way, what _are_ the
> implications for robotically shipping a "rock" from
> the asteroid belt to L5, probably (I have no clue how
> to do the math) simpler than diverting something in a
> profoundly non-circular solar orbit, like an earth's
> orbit transiting asteroid, if one is willing to be
> patient.
>
Forget asteroid belt rocks, there are NEOs which can be captured with
just 169m/s Delta V. Lets assume a Delta V requirement might be 300m/s.
Exhaust velocity might be 30,000 m/s, so you'd need to "burn" 1% of the
asteroid, or 80 tons in a plasma engine. That's why I keep asking
about Oxygen fuelled plasma engines, since oxygen is a fuel that can be
got from most asteroids, or the moon.
> And, what constitutes a big enough "rock" to be worth
> the effort?
>
NEOs - 8,000 tons is plenty for starters - it would:
1. Provide shielding for a base for dozens of people.
2. Allow, assuming suitable techniques, the manufacture of a 100 MW
solar array
3. Allow, assuming suitable techniques, a mission to be assembled to
fetch a NEO with a mass of 200,000 tons.
Mike Combs
news:i68801pgb180c7bfu...@4ax.com...
>
> Except most of our industrial processes work better in the presence of
> at least some gravity. It makes a lot of things a lot more
> convenient.
For any industrial process where some gravity is advantageous, don't forget
that a suitable substitute can be arranged for in an orbital facility by
having a portion of it rotate. On the other hand, if there are any
industrial processes where 0-G was where the advantage lay, one could have
that too; but couldn't have it on the lunar surface.
But the latter is not the primary argument for processing in HEO over the
lunar surface. The primary arguments are the gravity well issues, and the
continuous availability of sunlight in a sufficiently-high orbit. For as
long as a portion of an orbital facility can be made to rotate, there's
simply no reason to abandon these significant advantages just because we
need some material to settle or separate.
> I'd think you just chuck it into a crater from on high and then go
> strip mine it out. No 'landing it' necessary. Little to no
> atmosphere means you can use solar furnaces for smelting.
For 2 weeks out of every 4. In HEO, those solar furnaces can run 24/7. And
can be made arbitrarily large.
Kent Paul Dolan
> Kent Paul Dolan wrote:
>> "Malcolm Street" <mst...@internode.on.net> wrote:
>>> All you need to do is get a dinosaur-killer-sized
>>> asteroid into orbit closer than the moon without
>>> risking it hitting the earth.
>> No, and no. You don't have to start with something
>> 10 km in diameter, 200 m in diameter is a huge good
>> start [...]
> Right, but 200m is still way too big - that's
> about 8 million tons. For a first attempt, go for
> about 20m diameter - about 8,000 tons.
And that, on the other hand, strikes me as (much) too
small! <grin> My (long ago) submarine displaced 8000
tons, and that is (1) a single vessel, where we want
more the material for a fleet (or better, a
"swarm"), (2) something a person can (and I did)
move with the strength of a single arm, in a
frictionless medium, quickly and visibly seeing the
results, thus too "human scale" and prone to
inadvertant disaster caused by mere misapplication
of human strength, and (3) only sufficed to hold 145
individuals [and depended on the water above for
most of its shielding, with the partial result that
except for two of us, most submariners on nuclear
powered vessels _decrease_ their whole body
radiation exposure while underway and under water],
too few for a thriving orbital industry, which wants
thousands, to start, so that you can afford the
managers and the service industry personnel to be
onsite as well as the manufacturing and
transportation industry personnel. Look at all the
mass of the ISS, and yet we're down to just two
people at a time inhabiting all of that.
>> Now that Smart-1 has proved humankind capable of
>> doing space the slow and steady way, what _are_
>> the implications for robotically shipping a
>> "rock" from the asteroid belt to L5, probably (I
>> have no clue how to do the math) simpler than
>> diverting something in a profoundly non-circular
>> solar orbit, like an earth's orbit transiting
>> asteroid, if one is willing to be patient.
> Forget asteroid belt rocks, there are NEOs which
> can be captured with just 169m/s Delta V. Lets
> assume a Delta V requirement might be 300m/s.
> Exhaust velocity might be 30,000 m/s, so you'd
> need to "burn" 1% of the asteroid, or 80 tons in a
> plasma engine. That's why I keep asking about
> Oxygen fuelled plasma engines, since oxygen is a
> fuel that can be got from most asteroids, or the
> moon.
I'd like to propose a dual valued effort/energetics
metric, the "dark cost". That would be the energy
and people cost of bringing the technology to the
rock, installing it, making the rock ready to move
under solar power to its destination, full stop.
Anything that's "free to us once we set it going"
and "doesn't consume on-site human lifetimes to the
exclusion of other efforts" doesn't get counted, but
the cost of lugging the solar panels (and of
inhabiting the lugging tool) [is balanced against the
option of lugging the technology to turn part of the
mass _into_ solar panels (and people staying there
while it happens)] ... _is_ counted.
Under that metric, I wonder if Phobos and Deimos,
with permanent human settlements on them mining and
forwarding mass increments, aren't "dark cost close"
for mass wanted in high earth orbit? They have
masses of 1.08e+13 and 1.80e+12 metric tons,
respectively, which it would be the work efforts of
whole civilizations to exhaust, plus one would have
the option of sending refined materials, or
manufactures, rather than just raw materials. They
are small enough that you'd want to put the
settlements inside to avoid problems with near lack
of surface gravity.
http://www.solarviews.com/eng/mars.htm
>> And, what constitutes a big enough "rock" to be
>> worth the effort?
> NEOs - 8,000 tons is plenty for starters - it would:
> 1. Provide shielding for a base for dozens of
> people.
Probably sufficient for three dozen, not for a
gross, but thats a lot more than we orbit at
present.
> 2. Allow, assuming suitable techniques, the
> manufacture of a 100 MW solar array
I'm conflicted whether, for energy in the large, in
the end, despite all that sunlight being out there
and "for free", solar arrays will be competitive
with nuclear power plants. Solar arrays are
gargantuanly _awkward_ things, very vulnerable,
impossible to "harden", and we've already had
several partial or full "failed to deploy" problems
with fairly tiny ones used in satellites, IIUC.
> 3. Allow, assuming suitable techniques, a mission
> to be assembled to fetch a NEO with a mass of
> 200,000 tons.
Which in turn would be useful to go get some real
mass.
Trouble is, your 8000 tons are just about going to
suffice for _one_ substantial vessel, one big enough
to be long term self sufficient, so it can do that
task not once, but as its ongoing job of work, big
enough to have its own machine shops, carry
specialists to use them, and such, and now it is off
for a long time doing that one thing to the
exclusion of other commercially valuable efforts.
xanthian the unrealistic.
"More, mommy, I want _more_"!
Industrial strength decimal place mislocation
may follow, You Have Been Warned:
Things You Can Do with a Rock, the "Lebensraum"
version:
To an order of magnitude approximation, Phobos _is_
that "dinosaur killer", very roughly a 20 Km
diameter ball rather than a 10 Km diameter ball,
eight times as big.
http://www.solarviews.com/eng/mars.htm
For back of the envelope calculations, call it at 20
Km cube: [really, 13.5 Km x10.8 Km x 9.4 Km radii]; turn
it into living space at 4 m per "floor", throwing
away (using for other purposes) the rubble you
remove, it comes out to 200000 Km*Km of living space.
That's quite an improvement over that "100m
balloon", and lots easier to seal to make it
airtight: just walk around the outside, spray
painting it with sealer using an electrostatic paint
sprayer. Granted, rather a _lot_ of sealer; it might
take more than one worker to finish the job before
coffee break.
Froth it up (by "magic" for now) instead (for
insulation and sheer bulk) to turn it into something
like pumice at 1/10th its current density (with a
thin, tough "candy shell"), make your living space
with 10 cm thick walls, less an ignored fraction for
the dense harder surface coating, since in the
absence of gravity it doesn't need huge structural
strength except for the airtight outer skin, a
neglectable fraction of the whole. [It wouldn't be
all _that_ weak, however, oil tanker hull metal has
about that much mass per surface area, IIRC.]
Now, with shared walls you get 1.6e+8 Km*Km of
living area (since you can "live" on both sides of
all six interior walls of a cube in space), which
compares favorably to Earth's 1.2e+8 Km*Km of
exposed land area.
http://pages.prodigy.net/jhonig/bignum/qland2.html
It wouldn't need to feel "crowded", either, since
there's no impetus to make the floors closely
spaced; they could be on 100 m centers instead of
4 m centers.
You still have the problem of lugging all the
breathing gas to fill it though. That's why we have
the Oort cloud.
And once you finish building it, "just" add
thrusters and take it somewhere more interesting.
Now, class, let us consider uses for Ceres...
Rodney Kelp
"Malcolm Street" <mst...@internode.on.net> wrote in message
news:4203...@duster.adelaide.on.net...
> Bounty wrote:
>
>> Why oh why do I want to go all the way to that grey thing, when there's
>> more economical business to be done nearer home with the right rock
>> from outer space? This is a smart idea - was a smart idea... still
>> plain wishful thinking.
>>
> All you need to do is get a dinosaur-killer-sized asteroid into orbit
> closer
> than the moon without risking it hitting the earth. Funnily enough, I
> think a lot of people mightn't like that idea.
>
> Good luck being allowed to do it even without technical obstacles.
There are plenty of asteroids burried in the lunar crust.
Rodney Kelp
materials to build the moon base from moon materials. All you need do is
bring the technology there to build with. You don't need to shuttle
everything from the earth or an asteroid.
"Bounty" <boun...@lycos.com> wrote in message
news:1107269912.0...@c13g2000cwb.googlegroups.com...
Fred J. McCall
:"Fred J. McCall" <fmc...@earthlink.net> wrote in message
:news:i68801pgb180c7bfu...@4ax.com...
:>
:> Except most of our industrial processes work better in the presence of
:> at least some gravity. It makes a lot of things a lot more
:> convenient.
:
:For any industrial process where some gravity is advantageous, don't forget
:that a suitable substitute can be arranged for in an orbital facility by
:having a portion of it rotate. On the other hand, if there are any
:industrial processes where 0-G was where the advantage lay, one could have
:that too; but couldn't have it on the lunar surface.
:
:But the latter is not the primary argument for processing in HEO over the
:lunar surface. The primary arguments are the gravity well issues, and the
:continuous availability of sunlight in a sufficiently-high orbit. For as
:long as a portion of an orbital facility can be made to rotate, there's
:simply no reason to abandon these significant advantages just because we
:need some material to settle or separate.
Except if you do the processing in HEO you have to lift all the RAW
material (much higher mass) from somewhere. If you do the processing
on the lunar surface (using local raw materials) you're only lifting
the refined stuff out (at least an order of magnitude less mass to
lift).
:> I'd think you just chuck it into a crater from on high and then go
:> strip mine it out. No 'landing it' necessary. Little to no
:> atmosphere means you can use solar furnaces for smelting.
:
:For 2 weeks out of every 4.
Dig for 2, smelt for 2.
:In HEO, those solar furnaces can run 24/7. And
:can be made arbitrarily large.
And now every bit of stuff you have to move to/from a furnace is an
orbital change. No gravity at your furnace, so lots of 'normal'
separation processes won't work well.
If you dump it on the Moon, no fancy precision orbits are required.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Joe Strout
"Fred J. McCall" <fmc...@earthlink.net> wrote:
> Except if you do the processing in HEO you have to lift all the RAW
> material (much higher mass) from somewhere. If you do the processing
> on the lunar surface (using local raw materials) you're only lifting
> the refined stuff out (at least an order of magnitude less mass to
> lift).
Only if you're not making use of the entire buffalo -- er, lifted mass I
mean. Most plans assume that you do use it all; the leftover slag from
the refinement processes become your habitat shielding, which you need
anyway.
> :In HEO, those solar furnaces can run 24/7. And
> :can be made arbitrarily large.
>
> And now every bit of stuff you have to move to/from a furnace is an
> orbital change. No gravity at your furnace, so lots of 'normal'
> separation processes won't work well.
Not a significant orbital change if it's all in the same complex
(essentially the same orbit).
And where you want a gravity-style separation process, you simply use a
centrifuge (or the equivalent, a continuously rotating processing
module). Maybe 1/6 G isn't the amount of acceleration you need anyway.
And note that the "normal" separation processes inherent in doing
metallurgy on a planet also prevent you from making lots of potentially
useful alloys. The flexibility of orbital processing is going to be
hard to beat, once we get over the hump in R&D.
Best,
- Joe
Mike Combs
>
> Except if you do the processing in HEO you have to lift all the RAW
> material (much higher mass) from somewhere.
Joe has already made the point that the leftover slag is useful as radiation
shielding. If the slag weren't available for use as shielding, we'd have to
lift the equivalent mass of some other material anyway.
> If you do the processing
> on the lunar surface (using local raw materials) you're only lifting
> the refined stuff out (at least an order of magnitude less mass to
> lift).
Are you sure about that "order of magnitude" assertion? The oxygen is
valuable for breathing, making water, and as rocket oxidzer. The silicon is
useful for solar cells and glass-making. The metals are obviously useful.
When it comes to raw materials, space industries may use every part of the
pig but the squeal, as the saying goes.
> Dig for 2, smelt for 2.
There are advantages to continuous operation. What you can never get around
is that twice as much solar energy is available outside the shadows of
planets and moons.
> And now every bit of stuff you have to move to/from a furnace is an
> orbital change.
So? We tend to think orbital changes are a big deal because, after all,
it's "space travel". But minor orbital changes are a much easier kind of
space travel than the kind we're typically thinking about: namely getting
from where we presently sit into orbit.
> No gravity at your furnace, so lots of 'normal'
> separation processes won't work well.
No gravity at the focus of the space mirror, but there's no reason why there
couldn't be centrifugal forces at any other point in the material flow where
it's advantageous.
> If you dump it on the Moon, no fancy precision orbits are required.
I'd consider being isolated from your power supply 50% of the time (for two
weeks at a time) to be a greater problem in need of a solution than the
modest requirements for orbital station-keeping.
wbo...@visteon.com
I believe the lighter the molecule in the exhaust, the more efficient
the engine? If so, it might be better to make pellets of silicon (MW=
14) as we process the asteroid, charge them, and accelerate them using
an electrostatic engine. Oxygen has a molecular weight of 16, would be
rather corrosive in a high-temp exhaust, and is more useful than
silicon for other purposes.
Gene P.
On Tue, 15 Mar 2005, Mike Combs wrote:
[snip]
>I'd consider being isolated from your power supply 50% of the time (for two
>weeks at a time) to be a greater problem in need of a solution than the
>modest requirements for orbital station-keeping.
[snip]
I've got 2 different answers to this non-issue:
1. The Lunar Power Grid + electric furnace. Who cares if the electricity
comes from solar panels on the other side of the moon or from a great big
nuclear pile a couple of miles away...
2. Space furnace mirrors can point down at the lunar surface just as
easy as at an orbital processing facility...
--
Alcore Nilth - The Mad Alchemist of Gevbeck
alc...@uurth.com
Fred J. McCall
:I believe the lighter the molecule in the exhaust, the more efficient
:the engine? If so, it might be better to make pellets of silicon (MW=
:14) as we process the asteroid, charge them, and accelerate them using
:an electrostatic engine. Oxygen has a molecular weight of 16, would be
:rather corrosive in a high-temp exhaust, and is more useful than
:silicon for other purposes.
But do you really want to be spraying what are essentially high speed
bullets around where they can eventually hit other spacecraft? Better
something that isn't solid for your 'exhaust'.
--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world." -- Mary Shafer, NASA Dryden
David Summers
cheaper in Mexico (or even Nevada compared to New York)!
The fact is, transmitting power via cables over long distances is
expensive. The grid uses nearby sources, not far away ones. Losses on
long distance power cables become very large very fast.
-David
Joe Strout
"Gene P." <alc...@uurth.com> wrote:
> >I'd consider being isolated from your power supply 50% of the time (for two
> >weeks at a time) to be a greater problem in need of a solution than the
> >modest requirements for orbital station-keeping.
>
> I've got 2 different answers to this non-issue:
>
> 1. The Lunar Power Grid + electric furnace. Who cares if the electricity
> comes from solar panels on the other side of the moon or from a great big
> nuclear pile a couple of miles away...
Running power lines all the way around the Moon is itself a daunting
engineering challenge (though admittedly, one probably on the same order
as a mass launcher and large-scale orbital manufactury). A reasonable
solution, but not such a trivial one as to make lunar night a non-issue.
A nuclear power plant is also a reasonable solution, but again, it
doesn't offer the same flexibility or convenience as continuous sunlight.
> 2. Space furnace mirrors can point down at the lunar surface just as
> easy as at an orbital processing facility...
Can they? From where? There are no selenosynchronous orbits.
El Pollo Borracho
"Gene P." <alc...@uurth.com> wrote in message
news:Pine.LNX.4.44.050315...@uurth.com...
> 2. Space furnace mirrors can point down at the lunar surface just as
> easy as at an orbital processing facility...
Wrong. Think about it.
D Schneider
[...]
> The fact is, transmitting power via cables over long distances is
> expensive. The grid uses nearby sources, not far away ones. Losses on
> long distance power cables become very large very fast.
Well, depends on the long distance, I suppose. There's a intertie running
down eastern Oregon; probably from Bonneville on the Columbia river, and
probably to somewhere around Red Bluffs or Sacramento, so in excess of 300
miles doesn't seem strange. Also, 250 miles from Hoover Dam to LA.
Losses would go down with superconductor cabling, which is still
expensive, and the support equipment may still be prohibitively heavy.
But it looks like it might be practical and available within about the
same time as return to the moon.
/dps
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Ian Stirling
<snip>
> I believe the lighter the molecule in the exhaust, the more efficient
> the engine? If so, it might be better to make pellets of silicon (MW=
> 14) as we process the asteroid, charge them, and accelerate them using
> an electrostatic engine. Oxygen has a molecular weight of 16, would be
> rather corrosive in a high-temp exhaust, and is more useful than
> silicon for other purposes.
It's not quite this simple.
The velocity of gas molecules/atoms depends on the temperature and
rises with smaller particles at the same temperature.
This is why smaller is better.
If the particles are liquid, or solid, the mass is irrelevant.
Mike Combs
NASA didn't consider this a non-issue when they made the only detailed
studies of space industrialization using ET resources they ever did in their
history. In case you thought I was arguing from my imagination, or from
what happens to strike me as reasonable, I'm arguing from the NASA Summer
Studies on space settlement.
> 1. The Lunar Power Grid + electric furnace. Who cares if the electricity
> comes from solar panels on the other side of the moon or from a great big
> nuclear pile a couple of miles away...
A power grid spanning the entire globe of the moon would be a pretty
formidable industrial accomplishment. I can't see it happening in any
near-term future.
It would be a shame if we went to all the expense of developing nuclear
power on the moon just because we couldn't overcome our planetary chauvinism
long enough to develop solar power outside the shadows of planets. Nukes
are fairly high-tech, large mylar mirrors are pretty low-tech. I know which
is going to have the bigger power bill. With the space mirror, the heat
generated is used directly without any conversions and consequent efficiency
losses.
> 2. Space furnace mirrors can point down at the lunar surface just as
> easy as at an orbital processing facility...
No, actually, that's where you're wrong. The optical physics of it are such
that at several miles distance one would be forced to use mirror many times
bigger than otherwise (and also be forced to illuminate a much wider area
that what's desired). In discussing a High Frontier type solar furnace,
we're discussing mirrors perhaps one or two times the area of a football
field. To do what you propose would require mirrors the size of states or
small nations.
Mike Combs
> wbo...@visteon.com wrote:
>
> :I believe the lighter the molecule in the exhaust, the more efficient
> :the engine? If so, it might be better to make pellets of silicon (MW=
> :14) as we process the asteroid, charge them, and accelerate them using
> :an electrostatic engine. Oxygen has a molecular weight of 16, would be
> :rather corrosive in a high-temp exhaust, and is more useful than
> :silicon for other purposes.
>
> But do you really want to be spraying what are essentially high speed
> bullets around where they can eventually hit other spacecraft? Better
> something that isn't solid for your 'exhaust'.
Yes, but space is already criss-crossed with high-speed micrometeoroids. So
the only sensible question that needs answering is are we making a
significant contribution to an already-existing problem. At many levels of
scale, the answer is probably "no".
That said, I remember that in the "High Frontier" plan, it was proposed that
mass-drivers start out using pelletized Space Shuttle ET's for their
reaction mass, but at a fairly early point switch over to locally-produced
oxygen, which would vaporize on release. So the impression that I get is
that it's not an issue to be disregarded, but it's not a big issue.
Mike Combs
news:joe-8FA6AE.0...@comcast.dca.giganews.com...
>
> Running power lines all the way around the Moon is itself a daunting
> engineering challenge (though admittedly, one probably on the same order
> as a mass launcher and large-scale orbital manufactury).
I'm not even sure it would compare favorably with those items. I'm a little
bit vague on the mass budget for the orbital manufacturing facility O'Neill
proposed, but as for the mass launcher, I remember him commenting that the
components for the mass-driver itself would fit into a single Space Shuttle
cargo bay, although the components for the power supply would be several
times that.
> > 2. Space furnace mirrors can point down at the lunar surface just as
> > easy as at an orbital processing facility...
>
> Can they? From where? There are no selenosynchronous orbits.
Yet another complication. And the L-1 and L-2 points are so far away that I
think we'd be discussing mirrors bigger than continents.
Rick Jones
Would the dark/night side of a lunar power grid be cold enough to be
more easily (than on earth) constructed from superconducting
materials?
rick jones
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feel free to post, OR email to raj in cup.hp.com but NOT BOTH...
Paul F. Dietz
> A power grid spanning the entire globe of the moon would be a pretty
> formidable industrial accomplishment. I can't see it happening in any
> near-term future.
I suspect a power grid on the moon is considerably more difficult than
one on earth, even ignoring the difference in labor cost. A high voltage
conductor in dense air is insulated by that air, but in vacuum you'll be
constantly generating high energy ions and electrons in the surrounding plasma,
and possibly causing runaway discharge due to their collision with surfaces
and secondary ion production.
Paul
Cameron Dorrough
news:pZqdnULXMd7...@dls.net...
That's assuming that you'd run the cables suspended above the surface
somehow...
If you were serious, you'd probably direct bury them - AIUI, moon dust is a
great insulator.
Cameron:-)
Kent Paul Dolan
> There are no selenosynchronous orbits.
One. You're orbiting in it.
xanthian.
D Schneider
> {...] but in vacuum you'll be
> constantly generating high energy ions and electrons in the surrounding
> plasma, and possibly causing runaway discharge due to their collision
> with surfaces and secondary ion production.
>
How much plasma is there on the Moon? I would have thought that the
density of earth's atmosphere falls off rapidly after LEO (isn't drag
negligible by MEO?). Does the solar wind have enough density to produce
arcing?
Dr John Stockton
Mar 2005 02:07:36, seen in news:sci.space.tech, Rick Jones <f...@bar.baz.
invalid.retro.com> posted :
>
>Would the dark/night side of a lunar power grid be cold enough to be
>more easily (than on earth) constructed from superconducting
>materials?
I believe that I have read that for an east-west line in mid-northern
latitudes it would be enough to put the cable at the south side of the
base of a trench-and-berm, in such a fashion that the cable could "see"
a large amount of "sky" without ever "seeing" either the Sun or any
surface illuminated by the Sun. Present-day "high-temperature
superconductors" would be used.
/\
/ | \
/ | \ <-- direction of sun's rays
/ | \
/ |
-----------/ | /---------
| /----/
| /----/
|oo /
+---+
--
© John Stockton, Surrey, UK. *@merlyn.demon.co.uk / ??.Stoc...@physics.org ©
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)
Gene P.
On Wed, 16 Mar 2005, Joe Strout wrote:
>> 1. The Lunar Power Grid + electric furnace. Who cares if the electricity
>> comes from solar panels on the other side of the moon or from a great big
>> nuclear pile a couple of miles away...
>
>Running power lines all the way around the Moon is itself a daunting
>engineering challenge (though admittedly, one probably on the same order
>as a mass launcher and large-scale orbital manufactury). A reasonable
>solution, but not such a trivial one as to make lunar night a non-issue.
>
>A nuclear power plant is also a reasonable solution, but again, it
>doesn't offer the same flexibility or convenience as continuous sunlight.
While admittedly not most efficient for the 1st such plant, if space based
industrial civilization takes any sort of toe hold, the moon will develop
such infrastucture in the same way that the Earth did... (i.e. Nuclear
and fossil power plants in the Southern USA sell a *lot* of power to the
the Northeast over the national power grid.)
>> 2. Space furnace mirrors can point down at the lunar surface just as
>> easy as at an orbital processing facility...
>
>Can they? From where? There are no selenosynchronous orbits.
I was thinking of Lagrange points here... but the fact is that if you
build several (3 at a minimum) sets of mirrors in lunar orbit, they can
"trade off" power duties to lunar ground targets as they pass by
overhead...
I'm basically a skeptic of human nature though... I don't think there will
ever be solar power satellites or really big solar mirror farms for the
same basic reason:
The ability to focus a power beam at any distance is equivalent to a space
weapon of incredible power. No Government will ever allow it... unless
there's been a major war and only one government has access to space.
Building big Photovolatic arrays *might* be allowed though... as long as
the facility it's attached to doesn't have a railgun.
Gene P.
Gene P.
Clearly you are unaware of the fact that we *do* ship *A LOT* of power
over the grid to the Northeast and West Coasts...
That's why a generator fault near Chicago or in Canada can cause cascade
failure of the grid in New England... because without the long-haul power
imports, the local grid sources *can't* carry the load.
One of the leading exports of the south is generated power. We didn't let
our environmentalists and carping shouts of NIMBY! NIMBY! stop us from
continuing to build power plants from 1960-1990. (NIMBY = "Not In My Back
Yard")
Mississippi has more than enough Nuclear power to carry the entire
(mostly agricultural) state... Nonetheless, it *also* operates several of
the most modern and up to date fossil power plants in the nation as
well...
And the Texas sub-grid sells a lot of power to the West Coast...
Gene P.
Fred J. McCall
:Then why don't we use such things on Earth? Nuclear power is WAY
:cheaper in Mexico (or even Nevada compared to New York)!
:
:The fact is, transmitting power via cables over long distances is
:expensive. The grid uses nearby sources, not far away ones.
Not these days. The grid uses whatever power is there and it can come
from all sorts of places. This is why when there is a power failure
these days it usually takes down huge geographic areas of the grid
:Losses on
:long distance power cables become very large very fast.
Well, no. Ever heard of DC?
Total transmission losses and distribution losses in the US amount to
around 7.5%. This includes all the voltage step up and step down
losses as well as line losses. This is hardly 'very large'.
Paul F. Dietz
> How much plasma is there on the Moon? I would have thought that the
> density of earth's atmosphere falls off rapidly after LEO (isn't drag
> negligible by MEO?). Does the solar wind have enough density to
> produce arcing?
The concern would be that there would be a runaway discharge from
secondary ions. You wouldn't need much to get that process started.
Paul
Sander Vesik
>
> If you were serious, you'd probably direct bury them - AIUI, moon dust is a
> great insulator.
Its a great thermal insulator - this does not automaticly mean it is
also a great electrical insulator (especially if fused by the electricty
first).
--
Sander
+++ Out of cheese error +++
James Nicoll
Gene P. <alc...@uurth.com> wrote:
>
>I'm basically a skeptic of human nature though... I don't think there will
>ever be solar power satellites or really big solar mirror farms for the
>same basic reason:
>
>The ability to focus a power beam at any distance is equivalent to a space
>weapon of incredible power. No Government will ever allow it... unless
>there's been a major war and only one government has access to space.
>
>Building big Photovolatic arrays *might* be allowed though... as long as
>the facility it's attached to doesn't have a railgun.
I've been thinking about this ever since I noticed that Dyson
Swarms + Phased Arrays + short wavelength beams = the ability to
evaporate Earth mass worlds in about a week anywhere in the visible
galaxy and the nearer galaxies (limited by orbital predictions). On
the one hand, it explains the Fermi Paradox but I think in the short
run, AU range beams aren't quite the centralizing force they appear
to be.
Once the range is long enough, it gets hard to nail ships
that have some kind of on-board motive power. A large enough swarm
may be able to get close enough to destroy a pesty array. Some laser
designers are less robust that others: the X-Ray lasers that were
discussed last year have 100% reflective mirrors until they are
jostled by an atomic diameter or so, for example, after which heat
losses will make the mirrors turn into plasma somewhere between
"Uh" and "Oh". Kinetic Friendship Packages are one way to make this
happen.
Arrays are big and will have huge, targetable radiators. Other
arrays can used a la MAD to limit antisocial applications of beams. In
this case, balkanization limits tyranny. If the Mercurial Power Company
and Harsh Overlords LLC starts talking about "natural monopolies", it
may be best to just open fire on their corporate HQ.
Even with terawatt beams, it takes a surprisingly long time to
evaporate even small asteroids. Dig in and invest in _good_ mirrors.
James Nicoll
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Joe Strout
"Gene P." <alc...@uurth.com> wrote:
> >> 2. Space furnace mirrors can point down at the lunar surface just as
> >> easy as at an orbital processing facility...
> >
> >Can they? From where? There are no selenosynchronous orbits.
>
> I was thinking of Lagrange points here... but the fact is that if you
> build several (3 at a minimum) sets of mirrors in lunar orbit, they can
> "trade off" power duties to lunar ground targets as they pass by
> overhead...
Neither of those is anywhere near as easy as focusing light at an
orbital processing facility. The distance from any Lagrange point to
the Moon is huge, requiring an enormous mirror and resulting in a rather
broad hot spot. And in the case of several mirrors in low lunar orbit,
you've now got rapid tracking issues -- not insurmountable, to be sure,
but clearly not as easy as a mirror as part of your facility, facing the
sun 24x7.
> I'm basically a skeptic of human nature though... I don't think there will
> ever be solar power satellites or really big solar mirror farms for the
> same basic reason:
>
> The ability to focus a power beam at any distance is equivalent to a space
> weapon of incredible power.
Nonsense. The microwave power beam from a solar power satellite has
half the power density of sunlight. You could walk right through it and
probably wouldn't even notice.
I don't think that mirrors could focus light on Earth's surface enough
to cause major damage, either.
Mike Combs
>
> I'm basically a skeptic of human nature though... I don't think there will
> ever be solar power satellites or really big solar mirror farms for the
> same basic reason:
>
> The ability to focus a power beam at any distance is equivalent to a space
> weapon of incredible power. No Government will ever allow it... unless
> there's been a major war and only one government has access to space.
You need to read some more on the SPS proposal. The power beam proposed
would have zero usefulness as a weapon. It's a beam that requires the
active cooperation of its target (I'm referring to the phased array pilot
signal).
D Schneider
Can you explain in more detail how the secondary ions would be formed?
What are you seeing as the primary ion, and what atoms become the
secondary ions?
D Schneider
> Cameron Dorrough <cdor...@nortonconsultants.com> wrote:
>>
>> If you were serious, you'd probably direct bury them - AIUI, moon dust
>> is a great insulator.
>
> Its a great thermal insulator - this does not automaticly mean it is
> also a great electrical insulator
No, but those properties are often related; electron mobility plays a role
in each.
> (especially if fused by the electricty first).
Silicates tend to form glass; I'm not sure what the particular minerals
most common in lunar regolith would form into.
Paul F. Dietz
> Can you explain in more detail how the secondary ions would be formed?
> What are you seeing as the primary ion, and what atoms become the
> secondary ions?
Primary ions would be ambient plasma ions. Secondary ions would be ions
sputtered off surfaces after impact by other ions or electrons.
Paul
D Schneider
> Primary ions would be ambient plasma ions. Secondary ions would be ions
> sputtered off surfaces after impact by other ions or electrons.
>
So what is the flux of ambient plasma ions at the lunar surface?
Paul F. Dietz
> Paul F. Dietz <di...@dls.net> wrote:
>
>> Primary ions would be ambient plasma ions. Secondary ions would be ions
>> sputtered off surfaces after impact by other ions or electrons.
>>
>
> So what is the flux of ambient plasma ions at the lunar surface?
If the multiplication factor is > 1, you just need one to get the
process started, so the initial ion density isn't important.
Paul
Earl Colby Pottinger
> Nonsense. The microwave power beam from a solar power satellite has
> half the power density of sunlight. You could walk right through it and
> probably wouldn't even notice.
think you are wrong there. As you walk thru the beam you will probably
think it is a very hot day and go looking for a drink. Powersats promote
beer sales, that is why there is a sercet cabal of German Brewmasters behind
the push for space power.
> I don't think that mirrors could focus light on Earth's surface enough
> to cause major damage, either.
High school math is your friend. Basicly, a point source from an orbiting
mirror reflecting to Earth's surface with expand in width 1/100 it's attitude
on the surface.
Simple model: Orbit a mirror at 200 KMs and see how much it can increase
light desity on Earth if it is perfect.
Min. Spot size on Earth 2KM.
1KM mirror, - Solar flux increase 25%, Total flux 125% - Just a hot day.
2KM mirror, - Solar flux increase 100%, Total flux 200% - Feel the heat.
4KM mirror, - Solar flux increase 400%, Total flux 500% - Now that is
getting hot!
The problem is 200KM is very low, you have major orbital decay problems, the
transit time across the sky is very fast so you need a lot of mirrors or alot
of downtime.
So let's try 1000KM.
Min. Spot size on Earth 10KM.
1KM mirror, - Solar flux increase 1%, Total flux 101% - This will not be
noticeable.
2KM mirror, - Solar flux increase 4%, Total flux 104% - Not much better.
4KM mirror, - Solar flux increase 16%, Total flux 116% - Just noticable!
Basicly mirrors need to be min of 1% in diameter of thier attitude to achive
even a 100% increase of the solar flux. Thier use as a weapon does not make
sense.
Earl Colby Pottinger
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