Space review: The vision thing

"TangoMan" wrote in message
news:5Xywb.488340$pl3.21449@pd7tw3no...

SPS doesn't need to be 2.5 GW. This issue just focuses on optimization
issues. It's not an inherent characteristic.

Actually, it does need to be very close to that to even be remotely viable
comercially. You have to put a SPS at GEO so it's in sunlight as much as
possible but is still close to Earth.

But if it's in GEO, there are strict limits on how small the array can be to
accurately focus enough usable power on a single rectenna. If you put a
small SPS into GEO, you can't get enough power out of it to do anything. The
math is that it would *have to* be miles-square, how many miles each way
depends on the efficiency of the collectors. Call is 20 mi^2

And if you have a miles-square array up there, you have to scale your mass
requirements appropriately. Most of the recent designs show
tens-of-thousands of metric tons, and to tell you the truth that may just
have been for the intermediate-scale "pilot projects", an actual commercial
SPS might even be much larger than that.

The only way around that would be to have a smaller SPS in LEO, but then it
doesn't get constant sunlight and isn't big enough to do much good anyway.
So it's easier to haul uphill, but once you get it there you don't get any
juice from it.

Mass isn't really the driving factor other than in flawed SPS business
plans. You need several thousand individual solar collectors, and even
deployed they are too big to be launched in tandem. So it's either one
booster per module, or you have to assume some totally new way of
getting
into orbit that doesn't even involve rockets. Or you have to assume
space
mining, in which case assembling an SPS will be the last of a long
string
of
things you have to learn how to do.

The beauty of framing an argument is that you hope people will be
constrained by your flawed scenario. Of course, you completely leave out
the
option of orbital assembly of launched components.

umm, that's exactly what I've been talking about, actually. Each "module"
deploys to a couple hundred feet on a side. But for the complete collector
array you need literally thousands of them, and even stowed for launch they
will at best fit one-to-a-launcher (one design shows a 600'x600' array
stowing down to a 36'x21' cylinder, which is too wide for the shuttle's
cargo bay and probably too wide for most unmanned boosters that we have
today).

Same thing for the transmitter and the miscellaneous tooling and rigging you
need. I'm assuming that that part would be more "optimizable" than the solar
cells, figure about half as many boosters needed for the "pointy end" and
the infrastructure stuff.

This allows for
optimization of the mass in the launch vehicle and then later optimization
for the SPS platform.

again, you can't compress the raw materials much farther, unless somebody
invents something completely new that is only microns thick and is a highly
efficient sunlight-trapper, or whatever.

Of course, my caveat is that this process is most
appropraite to a SPS test platform and is not economic for large scale
implementation.

in which case you'd have to start from scratch anyway, so what was the point
of the test article?

Sure it makes sense but only when you proceed on unstated assumptions.
Primary among them is that there is some reason to establish all that
infrastructure. Absent consideration of SPS as a driver, I ask you what
we're going to need a lunar or NEO mine for, a smelter, etc?

3He, maybe some uranium, all kinds of rare things that would turn a profit
if you go out to space to get them. It's theoretically possible that at some
point we get into a serious water shortage and need all the H2O ice out in
our backyard, but I kind of doubt that'll ever happen. Be nice if we *could*
go get it, though.

If you're waiting for that orbital infrastructure to be in place before
embarking on SPS or other ventures, then you're going to be waiting a long
time because each step in the process of orbital development is
interdependent on other steps, and they won't develop in a piece meal
fashion. There needs to be a driver like SPS that *pulls* all of the
ancillary industry into orbit. Once established that industry benefits a
range of ventures not just SPS.

please, not the spinoff thing again.

Why? What's magic about an SPS? It's just a bad idea that has to do with
spaceflight, lots of other worthier goals to focus our efforts on.

The fact that you can't discern that SPS is not a space activity but a
commerical activity that serves the terrestrial electricity market is
illustrative of the problem you're having in this thread.

?!?

anything having to do with SPS means "out of Earth's gravity well", which
rather by definition means "space", both in semantic and logistical terms.

(and no, the problem I had on this thread was I let one asswipe **** me off.
Will not happen again, and has nothing to do with any space/commercial
dichotomization you're thinking of).

If you're defining activities as *space* and not commerical, then you're
going to have a more difficult time in serving a societal need.

definitely true, but I've been deliberately avoiding any sociological issues
and focusing on logistics. yes, there would be pushback on a massive "death
beams from outer space" project. No, that opposition would not be rational.

there are plenty of logical reasons to kill SPS, you don't need the boogey
man.

There may indeed be worthy spaceflight goals, but they are looked upon
akin
to charity, not a benefit to society. Reliable baseload power that is
clean
is a benefit to society. It matters not a whit that it comes from space.

Christ. Yes it *does*.

The tiny little fact that your generator is in Earth orbit means that the
entire thing carries a startup cost 50% higher than just building another
gas or coal plant on the ground. It also means that for the first ten or fif
teen years of operation, your base rate for the beamed power is going to be
two or three times the rate of the juice coming out of a coal or gas plant.
And it means that *maybe*, if you realize massive economies of scale as you
operate your SPS, that 15-25 years down the road your "clean" power is going
to still cost 40-60% *more* than what's on the grid now.

Unless, of course, you are just assuming into existence the space
manufacturing capability you mentioned. In which case, you need to make sure
you've allocated part of the massive development costs for all those space
tugs and mining rigs on Ceres or wherever. They'll cost a large fortune, too
(quite possibly *more* than simple boost-from-Earth), and lots of the
revenue from a SPS would be sucked into repaying for the infrastructure.

I'd suggest you start with a Google search for "solar power satellites" and
read some of the analyses that have been done in teh last five years. They
all reach the same conclusion: SPS is massively unaffordable, a sheer
boondoggle.

--
Terrell Miller


"Very often, a 'free' feestock will still lead to a very expensive system.
One that is quite likely noncompetitive"
- Don Lancaster

On Mon, 24 Nov 2003 12:59:48 -0800, Mary Shafer
wrote:

Nuclear power, which isn't indirectly (or directly) sun-driven. It
can make all the watts we need.

....Hear! Hear! And if we run out of fuel, we can always toss in the
hippie peacenik anti-nuke perverts as an alternative fuel source until
the breeder reactors catch up to the demand :-)

OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr

"Terrell Miller" wrote ...
I'd suggest you start with a Google search for "solar power satellites" and
read some of the analyses that have been done in teh last five years. They
all reach the same conclusion: SPS is massively unaffordable, a sheer
boondoggle.

http://www.google.com/search?q=%22so...+satellites%22
1. http://www.spaceref.com/directory/fu...er_satellites/
(a list of studies and articles)
1a. http://www.spaceref.com/redirect.ref...S.html&id=2558
(first entry from list)
Conclusions
===========
"An evolutionary pathway, where each technology is developed and brought on
line in a way to minimize risks, is a necessary prerequisite to development of
commercial satellite solar power systems. The program suggested, large-scale
photovoltaic application on Earth, beamed power in space, and construction of
a space infrastructure, could lead to development of all of the elements of a
satellite power system and demonstration at the appropriate large scale. This
would reduce the risk associated with a project at the necessarily large scale
of SPS sufficiently that it may be reasonable to consider such a project as a
commercial venture."

Can this be summarised as "SPS is massively unaffordable, a sheer boondoggle" ?
I think not.

Your assertion is thereby proven incorrect from the very first Google link

Next time try not to say things that are a) Untrue and particularly b) Easily
proved to be untrue.

"Paul Blay" wrote:

Next time try not to say things that are a) Untrue and particularly b) Easily
proved to be untrue.

That's pretty much his pattern throughout the discussion. He claims
to want and support SPS, yet closes his mind to any but negative
evidence.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

"Paul Blay" wrote in message
...

Your assertion is thereby proven incorrect from the very first Google link

Next time try not to say things that are a) Untrue and particularly b)
Easily
proved to be untrue.

Thanks for saving me from the need to issue a rebuttle. Good link, BTW.

TangoMan

On Mon, 24 Nov 2003 20:04:46 GMT, in a place far, far away, Michael
Walsh made the phosphor on my monitor glow in
such a way as to indicate that:


It is really hard to make a statement in these newsgroups that can
be assumed to be regarded as true by most of the other posters,
but I will try one.

The first operational SPS will be assembled from pieces constructed
from earthly materials and delivered to orbit from earth.

I seriously doubt that. The first pilot plant may be, just to test
the concept, but I doubt if a commitment will be made to operational
SPS absent an infrastructure that allows them to be built from
extraterrestrial materials, unless we get a skyhook up, or really
cheap launch from nanotech.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

On Tue, 25 Nov 2003 21:15:59 -0500, in a place far, far away, "Terrell
Miller" made the phosphor on my monitor glow
in such a way as to indicate that:

"TangoMan" wrote in message
news:5Xywb.488340$pl3.21449@pd7tw3no...

SPS doesn't need to be 2.5 GW. This issue just focuses on optimization
issues. It's not an inherent characteristic.

Actually, it does need to be very close to that to even be remotely viable
comercially. You have to put a SPS at GEO so it's in sunlight as much as
possible but is still close to Earth.

There are actually many SPS concepts that are not in GEO, and not that
large per satellite.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

On Mon, 24 Nov 2003 19:57:36 GMT, in a place far, far away, Michael
Walsh made the phosphor on my monitor glow in
such a way as to indicate that:


Intelligently designed in the sense that they didn't start with first
principles to achieve low cost--find a large market, and satisfy it.

Well, the large market for which the original launch rockets were
designed was military and the requirement was to dump a warhead
on an enemy.

That wasn't a large market in the sense that I'm discussing.

--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org

"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers:

Rand Simberg wrote:

On Mon, 24 Nov 2003 20:04:46 GMT, in a place far, far away, Michael
Walsh made the phosphor on my monitor glow in
such a way as to indicate that:

It is really hard to make a statement in these newsgroups that can
be assumed to be regarded as true by most of the other posters,
but I will try one.

The first operational SPS will be assembled from pieces constructed
from earthly materials and delivered to orbit from earth.

I seriously doubt that. The first pilot plant may be, just to test
the concept, but I doubt if a commitment will be made to operational
SPS absent an infrastructure that allows them to be built from
extraterrestrial materials, unless we get a skyhook up, or really
cheap launch from nanotech.

Well, like I said in my first sentence.

Does this mean that you believe that no operational SPS will be
built until a thriving infrastructure is in place on the Moon, built
for some other purpose?

I doubt any infrastructure for building a series of SPS orbital
installations from extra-terrestial sources would happen until a
multiple set of IOC (Initial Operational Capability) SPS showed economic
promise.

I believe this would be more than what I would consider a
pilot plant.

Mike Walsh

Rand Simberg wrote:

On Mon, 24 Nov 2003 19:57:36 GMT, in a place far, far away, Michael
Walsh made the phosphor on my monitor glow in
such a way as to indicate that:

Intelligently designed in the sense that they didn't start with first
principles to achieve low cost--find a large market, and satisfy it.

Well, the large market for which the original launch rockets were
designed was military and the requirement was to dump a warhead
on an enemy.

That wasn't a large market in the sense that I'm discussing.

I don't want to carry this discussion too far, as I believe I understand
the differences in the markets. I merely reject the argument that the
military rockets were not intelligently designed. They were, as many
space enthusiasts have pointed out, and example of ordnance rather
than commerce.

They have hung on for a long time because the vehicles exist and they
were developed using military money.

One of the lowest cost launchers available the Rokot has a distinctly
military background.

Mike Walsh