For those of you who may have read my article about planetary chauvinism
"Somewhere Else Entirely" at
http://members.aol.com/howiecombs/somewhere_else.htm, I just wanted to
let you know that I did have to back away from one of my assertions, and
I wrote a bit more to clarify some issues. Dr. David Criswell noted
some critical things I'd said about his LSP proposal, and we resumed our
previous debate on the merits of LSP vs. lunar-resources-derived SPS in
GEO. In my article I had asserted Criswell had not made sufficient
comparisons between his proposal and the O'Neill one. After some
discussion, I followed that paragraph with a parenthetical "(But I may
now need to retract at least this point. )" which was
a hyperlink to the following:

Lunar Solar Power Stations vs. The O'Neill Proposal

In May of 2006, Dr. David Criswell became aware of this article
and contacted me to resume our debate about the relative merits of Lunar
Solar Power (LSP) stations vs. lunar-resources-derived GEO SPS.
Dr. Criswell said that all of his comparisons were toward the
GD-Convair study, which included SPS where 90% of the construction
materials were lunar-derived (SSI later calculated this number could be
boosted to 99% for SPS designs optimized for use of lunar materials).
I'm sure my previous comment in this article would have been based on me
going through the Criswell papers looking specifically for references to
O'Neill or to manufacturing in HEO. Dr. Criswell went on to say he had
calculated LSP could provide power at a cost 1/50 that of power
delivered from SPS built as O'Neill had recommended.
Interestingly, Criswell said the GD-Convair study judged the
lunar-material-derived SPS option less risky than the Earth-launched one
for several issues, among them the environmental damage which would
doubtless be done to the upper atmosphere of Earth by all of those
thousands of mega-rockets thundering upward.
One very good point Dr. Criswell raised was that GEO SPS might
suffer from an orbital debris problem absent from the lunar surface. My
take on this is that hopefully a significant manned operational
capability in GEO might mean a better ability to manage and combat the
debris problem. But Criswell relates the severity of this hazard with
the surface area of the satellites in GEO. To say that SPS would lead to
a significant increase in this area is putting it mildly, to say the
least.
He says that my emphasis on the day/night cycle of the moon and
my assumption of a 2-to-1 advantage for GEO is wrong, making the point
that GEO SPS, being a baseload (flat) source of power, must be similarly
oversized around 2x in order to meet peak power demands. But I'm not
convinced this is the best argument, since an oversized GEO SPS can
obviously be selling excess power to secondary markets during off-peak
hours.
Despite the fact Dr. Criswell brought up much new and helpful
information and helped me appreciate certain aspects of LSP a bit
better, I still can't entirely rid myself of the conviction a planetary
bias may be involved here. When he says, "The Moon exists. You do not
have to build it, and you can use its materials," I think we're veering
from the point. The O'Neill proposal agrees the moon is the right source
for the materials, and I don't think our choice is between building an
orbital ore refinery or not, it's between building a refinery in orbit
or on the lunar surface. Ditto manufacturing facilities.
It can't be denied lunar materials take a much longer path in
the O'Neill scenario vs. LSP, and Criswell rightly points out that the
more steps, the greater the expense. But lunar lift costs are a one-time
expense. The 50% duty cycle resulting from the moon's day/night cycle is
an operational disadvantage which lasts the lifetime of the power plant.

On the other hand, there are some at SSI who tell me there are
too many unknowns to conclude that Criswell isn't right, and that power
beaming from the moon should not present major problems.
I'll say that if Dr. David Criswell has come up with an
alternative to SPS which can undersell it by a factor of 50, then he's
done more to advance us toward space settlement in recent decades than
anyone. There could be no doubt his LSP scenario would lead to the High
Frontier. For example, any universe in which many thousands of square
kilometers of the moon's surface is being coated in photovoltaic arrays,
the manufacture of a lunar mass driver (the most massive part of which
would be its PV array) would certainly be done on the lunar surface from
local materials instead of it being sent up as a kit from Earth. Thus,
in a future Criswell presents us, an important component of the O'Neill
vision becomes trivially easy to manufacture.

Regards,

Mike Combs

The problem with Criswell's idea isn't that it doesn't work; it's the
startup costs to get it to work.

Startup costs for Earth launched SPS is about $3-10 billion, and from
what I've seen payback is about 3 years or so.

Startup costs for lunar power is about $100+ billion.

If you were a politician would you sign off on a highly risky lunar
power system for $100 billion? I wouldn't. You might be about to swing
$3-10 billion.

$3-10 billion might be fundable, particularly if it secured supplies
of energy and reduced dependence on politically unstable regions.

Indeed, $3-10 billion might be raisable from private sources.

On 02/06/06, Combs, Mike wrote:
> For those of you who may have read my article about planetary chauvinism
> "Somewhere Else Entirely" at
> http://members.aol.com/howiecombs/somewhere_else.htm, I just wanted to
> let you know that I did have to back away from one of my assertions, and
> I wrote a bit more to clarify some issues. Dr. David Criswell noted
> some critical things I'd said about his LSP proposal, and we resumed our
> previous debate on the merits of LSP vs. lunar-resources-derived SPS in
> GEO. In my article I had asserted Criswell had not made sufficient
> comparisons between his proposal and the O'Neill one. After some
> discussion, I followed that paragraph with a parenthetical "(But I may
> now need to retract at least this point. )" which was
> a hyperlink to the following:
>
> Lunar Solar Power Stations vs. The O'Neill Proposal
>
> In May of 2006, Dr. David Criswell became aware of this article
> and contacted me to resume our debate about the relative merits of Lunar
> Solar Power (LSP) stations vs. lunar-resources-derived GEO SPS.
> Dr. Criswell said that all of his comparisons were toward the
> GD-Convair study, which included SPS where 90% of the construction
> materials were lunar-derived (SSI later calculated this number could be
> boosted to 99% for SPS designs optimized for use of lunar materials).
> I'm sure my previous comment in this article would have been based on me
> going through the Criswell papers looking specifically for references to
> O'Neill or to manufacturing in HEO. Dr. Criswell went on to say he had
> calculated LSP could provide power at a cost 1/50 that of power
> delivered from SPS built as O'Neill had recommended.
> Interestingly, Criswell said the GD-Convair study judged the
> lunar-material-derived SPS option less risky than the Earth-launched one
> for several issues, among them the environmental damage which would
> doubtless be done to the upper atmosphere of Earth by all of those
> thousands of mega-rockets thundering upward.
> One very good point Dr. Criswell raised was that GEO SPS might
> suffer from an orbital debris problem absent from the lunar surface. My
> take on this is that hopefully a significant manned operational
> capability in GEO might mean a better ability to manage and combat the
> debris problem. But Criswell relates the severity of this hazard with
> the surface area of the satellites in GEO. To say that SPS would lead to
> a significant increase in this area is putting it mildly, to say the
> least.
> He says that my emphasis on the day/night cycle of the moon and
> my assumption of a 2-to-1 advantage for GEO is wrong, making the point
> that GEO SPS, being a baseload (flat) source of power, must be similarly
> oversized around 2x in order to meet peak power demands. But I'm not
> convinced this is the best argument, since an oversized GEO SPS can
> obviously be selling excess power to secondary markets during off-peak
> hours.
> Despite the fact Dr. Criswell brought up much new and helpful
> information and helped me appreciate certain aspects of LSP a bit
> better, I still can't entirely rid myself of the conviction a planetary
> bias may be involved here. When he says, "The Moon exists. You do not
> have to build it, and you can use its materials," I think we're veering
> from the point. The O'Neill proposal agrees the moon is the right source
> for the materials, and I don't think our choice is between building an
> orbital ore refinery or not, it's between building a refinery in orbit
> or on the lunar surface. Ditto manufacturing facilities.
> It can't be denied lunar materials take a much longer path in
> the O'Neill scenario vs. LSP, and Criswell rightly points out that the
> more steps, the greater the expense. But lunar lift costs are a one-time
> expense. The 50% duty cycle resulting from the moon's day/night cycle is
> an operational disadvantage which lasts the lifetime of the power plant.
>
> On the other hand, there are some at SSI who tell me there are
> too many unknowns to conclude that Criswell isn't right, and that power
> beaming from the moon should not present major problems.
> I'll say that if Dr. David Criswell has come up with an
> alternative to SPS which can undersell it by a factor of 50, then he's
> done more to advance us toward space settlement in recent decades than
> anyone. There could be no doubt his LSP scenario would lead to the High
> Frontier. For example, any universe in which many thousands of square
> kilometers of the moon's surface is being coated in photovoltaic arrays,
> the manufacture of a lunar mass driver (the most massive part of which
> would be its PV array) would certainly be done on the lunar surface from
> local materials instead of it being sent up as a kit from Earth. Thus,
> in a future Criswell presents us, an important component of the O'Neill
> vision becomes trivially easy to manufacture.
>
> Regards,
>
> Mike Combs
>

--
-Ian Woollard

"Gravity is just a theory. We shouldn't be teaching it to children as
if were fact."
"The NSA would like to remind everyone to call their mothers this
Sunday. They need to calibrate their system."

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Ian Woollard

> Startup costs for Earth launched SPS is about $3-10 billion,
> and from what I've seen payback is about 3 years or so.
>
> Startup costs for lunar power is about $100+ billion.

Do you happen to have on hand the startup costs for GEO SPS derived from
lunar resources? I remember that O'Neill compared it to the costs for
the Alaska Oil pipeline, and I would think that would put it closer to
the lower numbers than to the higher one.

One of the things Criswell quoted back from the GD-Convair study (and
apparently what he uses for his comparisons) which didn't quite sound
right to me is that in a comparison of Earth-launched SPS vs.
lunar-derived SPS, costs were pretty much the same for the first 30
satellites, and that beyond that there was a slight price advantage for
the lunar resources option. I would rather have expected that use of
lunar resources would have made the first 30 satellites more expensive,
but beyond that point would achieve major cost reductions.

Regards,

Mike Combs

On 02/06/06, Combs, Mike wrote:
> One of the things Criswell quoted back from the GD-Convair study (and
> apparently what he uses for his comparisons) which didn't quite sound
> right to me is that in a comparison of Earth-launched SPS vs.
> lunar-derived SPS, costs were pretty much the same for the first 30
> satellites, and that beyond that there was a slight price advantage for
> the lunar resources option. I would rather have expected that use of
> lunar resources would have made the first 30 satellites more expensive,
> but beyond that point would achieve major cost reductions.

Earth launch options critically depend on how much it costs to launch.
Early studies by NASA were trying to find a use for the Shuttle, which
should be clear is a fairly expensive launch system. The numbers came
out pretty high with the Shuttle. (Gee, do you think?) I'm not sure
whether that's what the GD-Convair study did too.

O'Neill tried to finess around that by using lunar resources; and
Criswell is doing much the same trick.

I think in the long run that O'Neill's idea is good, and Criswell's
option is even cheaper, but people care more about short term costs,
even if long term costs are higher. They also care about risk even
more so.

I think the lunar resource options are higher risk, because you have
to be able to process the lunar material, and that's very researchy
thing right now. Also the mass driver can be done on paper, but
whether it would work when you scale it up, and stick it in a vacuum
and so forth is not clear. Well, it can definitely be made to work,
but I wouldn't like to bet that some of the first attempts don't blow
themselves to bits if the alignment is a bit off or something; or
otherwise fail the first few times.

There's clearly risk whenever you do something new for the first time.
And installing mass drivers on the moon isn't obviously easy-
presumably you would have to import most of the electronic components,
and assemble them there, you might be able to construct coils from
aluminum or calcium. But nobody has done anything like that, ever.
(Noteably, Moon dust is abrasive as hell, and destroys space suits in
a few hours.... little problems like that.)

>From earth launch perspective the numbers I've worked suggest that
expendable Falcon I's launched a *lot* (and I *really* mean a lot)
would bring the wallplug costs down to about $0.05/kWh, but I'm not
very happy with that option (Falcon I is too small to launch people
on, so a dirt cheap Falcon I wouldn't do much for space access, is
cheap, reliable electricity enough of a goal on it's own if it doesn't
lead to space colonisation????)

> Mike Combs

--
-Ian Woollard

"Gravity is just a theory. We shouldn't be teaching it to children as
if were fact."

From: Ian Woollard ian.woollard@...

>"O'Neill tried to finess around that by using lunar resources; and
>Criswell is doing much the same trick.
..........
>I think in the long run that O'Neill's idea is good, and Criswell's
>option is even cheaper,

Both Criswell and O'Neill want to pay for space activities by selling electricty to earth. Both require use of lunar regolith. The difference is O'Neall wants large numbers of people living and building things in space. It seems they are at two points on the same line of progress.

One possible sequence:

1. Low earth orbit SPS; built on earth and launched. This is absolutely required for validating technolgy and developing expertise. I expect upfront cost will be multiples of what some may now believe. (In other words, typical of many things.) After refinements, the economics become more favorable.

2. Development of robust equipment for processing lunar regolith. Llunar power transmission infrastructure can now be built without tremendous infusions of terrain mass.

Hopefully the lunar environment presents no show-stopping hurdles. Probably lunar dust will coat the solar collectors, reducing efficiency, and drive up costs. (What if charged dust gets kicked up every lunar day/ night cycle?)

Some technologies, like tele-operation will probably advance greatly between now and the advent of lunar mining. The time delay is quite short.

3. Lunar resources extracted in sufficient quantity and purity to manufacture good quality components. Until that time, maintanence may be a real problem. At this time mass drivers will become more common.

4. With mass drivers and maturing regolith processing capabilities, many big space construction projects become possible.

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Ian Woollard

> Earth launch options critically depend on how much it costs to launch.
> Early studies by NASA were trying to find a use for the Shuttle, which

> should be clear is a fairly expensive launch system. The numbers came
> out pretty high with the Shuttle. (Gee, do you think?) I'm not sure
> whether that's what the GD-Convair study did too.

I'd be real surprised if the study hadn't assumed the kind of massive
HLLV Boeing had touted for SPS launch.

> I think in the long run that O'Neill's idea is good, and Criswell's
> option is even cheaper,

So do you see the avoidance of lunar lift costs as outweighing the
operational disadvantage of power stations which only operate half the
time? But then I see you're saying people place greater emphasis on
startup costs than ongoing costs, so maybe you're only saying the
startup costs are less, which I might even agree with (though I think it
would be much closer than if the comparison were with Earth-launch).

> I think the lunar resource options are higher risk, because you
> have to be able to process the lunar material, and that's very
> researchy thing right now.

That was my take on it too. In fact, when Criswell told me that the
GD-Convair study had considered the lunar materials option to be lower
risk, I initially thought he had just said the opposite of what he had
meant. I would have accepted that the O'Neill proposal was higher risk
(but ultimately produces the cheapest SPS).

> From earth launch perspective the numbers I've worked suggest
> that expendable Falcon I's launched a *lot* (and I *really*
> mean a lot) would bring the wallplug costs down to about $0.05/kWh,
> but I'm not very happy with that option (Falcon I is too small to
> launch people on, so a dirt cheap Falcon I wouldn't do much for
> space access, is cheap, reliable electricity enough of a goal on
> it's own if it doesn't lead to space colonisation????)

I think a world in which SPS starts out with Earth-launch for the first
few might still lead down the High Frontier road provided that we became
seriously committed to SPS as a solution to global energy needs. That
kind of commitment might not happen prior to the era that at least a few
SPS are up there and functioning productively.

Regards,

Mike Combs