Hi Everybody,

It is interesting reading all the various ideas and explanations re
space settlements, but there are never going to be any until we
and/or others make it happen. The first step towards this must be to
bring down the cost of access to space.

Recently the Space Elevator fans have been holding a conference and
as a result, the subject came up at a discussion after a meeting of
the Mars Society UK (Scotland). It was suggested that a Martian
elevator ought to be combined with solar power satellites, then the
idea moved to doing this with terrestrial elevators. You could pipe
power down the elevator cable thereby making solar power sats more
environmentally acceptable, while at the same time making elevators
even more economical as in addition to giving cheaper access to LEO
their owners would be able to sell power.

Tourism to LEO is probably going to be the thing that really rings
down the cost of getting up there, but the elevator is certainly one
means of bring that within reach. What is the next stage though? How
do we get from the LEO Hilton to the first real O'Neill type
habitat? Any ideas?

Sorry I've not been very active lately, but I've been busy updating
my book-on-a-cd, "Universal Detectives a rough intro to cosmology".
It's a reference work now updated to 30th June 2004. If any of you
are intereted a free sample all about the 'X-Wind' is available at
http://ud.vstarnet.co.uk or in the members area of www.astra.org.uk .

Best wishes, Andy Nimmo.

Hi Andy:

I agree that the first step is bringing down the cost
of access to space, but I do believe that the shortest
path there is by using hypersonic single stage to
orbit (SSTO) carriers. I don't know why the aerospace
industry is not working on it as yet. If they build
those planes, the space industry would boom, and
pretty soon all the others dreams would come true. A
fleet of thirty SSTO hypersonic planes that make
regular trips to orbit, can produce a huge difference
in the amount of cargo and number of people send to
space.

The space elevator, I believe, will take more time to
develop, but I am certain that sooner or later we will
see them orbiting Earth.

Omar Vega

--- andynimmo wrote:

Spaceshipone got up to nearly mach 3. Orbital speed is about mach 25
or so. An SSTO is a ways in the future (I would be delighted to be
wrong about this). Not as far, I would guess, as the space elevator.
But why not an SSTS-O (single stage to sub-orbit), or even a TSTS-O?
Something that gets to, say, mach 7, and 150 km altitude? Then it
could meet up with a hypersonic, out-of-the-atmosphere skyhook (much
nearer term than SE). This just might work.

Xenophile (then again, maybe not)

--- In spacesettlers@yahoogroups.com, "Xenophile"
wrote:

> Something that gets to, say, mach 7, and 150 km altitude? Then it
> could meet up with a hypersonic, out-of-the-atmosphere skyhook
> (much nearer term than SE). This just might work.

I agree with Xenophiles prediction. A skyhook + hypersonic will be a
technologically lower hurdle and thus more likely.

TangoMan

I dont TangoMan. Why to stay with the little jump
when the solution of the problem, however difficult,
is at reach. In just 66 years, the man jumped from the
first fight to the land on the moon. But since then,
in the 35 years that passed (that is more that half
the previous period of time), men lost the courage to
invest in new technology. It's time to invest in the
hypersonic SSTO orbit now. Otherwise, will be a shame
for the people of hour times.

Omar Vega

--- victoriatangoman wrote:

--- In spacesettlers@yahoogroups.com, omar vega wrote:

> I dont TangoMan. Why to stay with the little jump

Because this little jump, as you call it, breaks the problem down
into smaller more achievable steps, and gets us to the solution
(orbital access) that much quicker.

It is easier to develop a craft that can economically get to Mach 18
or so, than one to get to Mach 25. Further, reentry issues are
lessened, and the payload ratio increases (you can't get away from
the rocket equation.)

Then in orbit we build a rotating, or a stationary, skyhook, the
grapple of which would rendevouz with the spaceplane and take over
the cargo and toss or transport it to a higher orbit. Once this
skyhook is built, it becomes a reusasble part of the infrastructure.

> when the solution of the problem, however difficult,
> is at reach.

What is at reach? I'm not aware of any technologies that enable
single stage to orbit vehicles to be developed immediately. Further
they have the reentry and payload issues to contend with.

TangoMan

Well, TangoMan, you may be right but I have some doubt
in the technical aspect of your proposal. If you have
two objets traveling in the same direction, one at
Mach 18 and the another at Mach 25, isn't there a
difference of Mach 7 between them? How it is going to
work? I'm just curious. Is there a Skyhook that could
resist the tension of the first impact?

By the way, I would like to asked you, If you don't
mind, of course (If you do, please accept my
apologies), why do you use the nickname "TangoMan". I
just wonder if you like Tango music, or if there is
another reason for that.

Maybe you are right in what you think, but I would
like to know more details.

Omar Vega

--- victoriatangoman wrote:

In a message dated 7/24/04 9:57:22 AM, oevega@... writes:

<< Hi Andy:

I agree that the first step is bringing down the cost
of access to space, but I do believe that the shortest
path there is by using hypersonic single stage to
orbit (SSTO) carriers. I don't know why the aerospace
industry is not working on it as yet. If they build
those planes, the space industry would boom, and
pretty soon all the others dreams would come true. A
fleet of thirty SSTO hypersonic planes that make
regular trips to orbit, can produce a huge difference
in the amount of cargo and number of people send to
space.

The space elevator, I believe, will take more time to
develop, but I am certain that sooner or later we will
see them orbiting Earth.

Omar Vega >>

What if we get a boost by selling the Air Force on idea of hypersonic single
stage to
orbit (SSTO) carriers as a way to create a fleet of new air-to-space fighters
and cargo planes so as to cut out the need for expensive oversea bases and
aircraft carriers? It could help create a series of useful prototypes and
trained staff that can be used to start up commerical transportation.

Carl E. Mullin
visionary artist and entrepreneur
homo asteralis
ravenart@...
www.ravenartstudio.com

The more you love, the more you can love-and the more intensely you love.
Nor is there any limit on how many you can love.
If a person had time enough, he could love all of the majority who are decent
and just.
-Robert A. Heinlein (Time Enough For Love)

"Fear is the mind killer. Fear is the little death that brings total
obliteration." -- Dune

Freedom, Immortality, and the Stars!

--- In spacesettlers@yahoogroups.com, omar vega wrote:

> Well, TangoMan, you may be right but I have some doubt
> in the technical aspect of your proposal. If you have
> two objets traveling in the same direction, one at
> Mach 18 and the another at Mach 25, isn't there a
> difference of Mach 7 between them? How it is going to
> work? I'm just curious. Is there a Skyhook that could
> resist the tension of the first impact?

Two points;

1.) for a rotating tether, all we're really concerned with is the
rendevouz velocity and the period of rendevouz. The rotating tether
will release the payload at Mach 25 but it need not be traveling at
that velocity.

For a very detailed treatment of skyhooks go here:
http://www.tethers.com/OrbitToOrbit.html

2.) for a stationary tether, the center on mass will have a velocity
of Mach 25, but points below will allow docking at anywhere from 70%
to 90% of orbital velocity (the longer the tower the lower the
docking velocity.

I'll attach a post from another group at the end of this message
that I spent an afternoon developing.

> why do you use the nickname "TangoMan". I
> just wonder if you like Tango music, or if there is
> another reason for that.

Dancing is one of the most effective methods of insuring marital
bliss! Years back it also allowed me to "punch above my weight
class" in the dating world and later while my wife was in medical
school, we really got deeply involved.

I didn't think that these names quite had the same ring:

FlamencoHombre
JiveGuy
ChaChaMan
RumbaDude
PasoDobleHombre
SambaHomem
WaltzMann
FoxtrotStud
VienneseWaltzGod
QuickstepBoy

Besides, Tango has a dramatic flair to the music and to the dance
that I really enjoy. Argentine Tango is quite an intimate and flashy
dance. I encourage all to participate (great women to men ratios for
you single guys :)

TangoMan
Here's the other post I mentioned:

Just thought I'd sit down and do a first order costing approximation
on how to lower launch costs and see where it leads me. I haven't
figured this out yet because I'm writing this as I go, so at the end
this may all turn out to be an exercise in determining it can't
work. Be warned that this'll probbly be an exercise of meaningless
numbers coming to a conclusion.

Space tourism seems to me to be a ready market if we can hit the
right price points and generate enough volume. So how do we do it.

I'm going to rely a lot on my notes which I've gathered from various
sources with varying degrees of attribution. It's kind of a big
jumble broken into topics.

Let me break the question into two sceanrios: orbital and sub-
orbital technology. I'll leave the orbital question for another time
or for someone else.

Suborbital obviously requires a secondary means to cover the
remaining distance. I'm going to look into an orbiting tower. Here's
the proposal.

A 1,380 km long tower. Center of mass orbiting at 1,250 km, a
docking station at 260 km, and a low gravity section at 1,640 km.
>From the docking station a winch is lowered to an altitude of 145 km
to intersect with a shuttle and then pulls the shuttle up to the
docking station.

What to build this out of. Spectra 1000 has a tensile strength of
3.0 GPa and a density of 0.97 g/cc but the Van Allen radiation belts
are going to make it pretty useless.

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=PCF007

Spectra 2000 is an improvement.
http://www.spectrafiber.com/pdfs/hon-pf-ps10-sp2000.pdf

While we're awaiting the perfection of carbon nanotubes, we can
consider carbon fibers. Thornel Carbon Fiber T-40 has a density of
1.81 g/cc and a tensile strength of 5.65 GPa.

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=ETHOR0

Taking into account a 2.4:1 safety factor, solar panels, electrical
cabling, counterwieght (10,000 tonnes), radiation shielding,
gondolas etc, the mass of material should be on the order of 15,500
metric tonnes. Of this about 2,800 tonnes should be carbon fiber.

How much will it cost?

First let me say that the study of optimization is very interesting
and leads down many paths. Very flowery isn't it? What I mean is
that rather than lifting all of that carbon fiber and counterweight
mass, it may be more efficient to send a probe to a NEO and bring
back liquid ammonia, liquid methane and water. Then build an orbital
Polyacrylonitrile plant. Disassociate the methane and ammonia into
constituent parts and reassemble as follows:

CH2=CHCH3 + NH3 + 3/2O2 --> CH2=CHCN +3H2O

This gives you acrylonitrile, the basic building block of PAN, or as
we know it, carbon fiber.

While you're at it bring back other mass which can be used for the
counterweight.

Is it worth it? I have no idea. But you see the benefit of having
some orbital infrastructure.

So let's assume you've got to lift all that mass into orbit.

Using the figures I have available to me:

The Proton 8K82K can lift 6,000 kg to a 1,500 km orbit at 63
degrees. If it could be launched from Kourou or Alcantara it could
get a boost in payload capacity. The cost of launch is $70 million.
It's probably lower than even that. Anyone have some good figures
for this?

So we need 2,583 launches at let's say $25,000,000 because of volume
discounts to the Chelomei Rocket Company. This should really boost
the Russian economy. Total price = $64.5 Billion.

Price of carbon fiber and fabrication: I have no clue. Anybody have
access to industry price lists. The stuff I get on the web is
consumer grade, small quantity carbon fiber, not aerospace grade,
high volume, high performance prices.

I found a reference to c.f. price per kg of $11 - $22 here:
http://www.hypercar.com/pdf/Hypercar_EVS19.pdf

Something else to consider; such a project is going to tax worldwide
carbon fiber capacity. It will consume 15% of worldwide output of
generic carbon fiber.

QUOTE
Over the past two years, we increased our installed capacity for
producing high-performance carbon fibers from 3.5 million pounds to
10.5 million pounds per year. That is about 25% of the total world
capacity.
END QUOTE
http://www.zoltek.com/company_information/history.shtml

So let's say it is $22/kg for the Thornel T-40. That amounts to
$61,600,000 and factoring in a fabrication cost multiple of 8x, we
get a wild assed guess of around $500,000,000.

Heck, let's just say the fabrication cost of the entire tower is $2
Billion.

Therefore, a launch cost of $64.5 Billion and a component cost of $2
Billion.

If we can launch twice a day, then we're looking at a 3 and a half
year construction schedule.

I know this is kind of disjointed, but I'm writing as it comes to me.

Back to the optimization alternative. We could first build a LEO
rotovator like I've mentioned in previous posts with a 15x-20x
mass:payload ratio which could then toss the payloads to our 1,250
km orbit. This would increase the capacity of the Proton rocket
payload to 21,000 kg to a 185 km orbit at 51.6 degrees, thus
reducing our total launches to 738.

The rotovator at a 20x mass ratio would mass at 21,000 kg x 20 = 420
tonnes. It would need an additional 20+ launches to assemble but
could reduce the total number of launches to the 1,250 km orbit. Of
course it would need dedicated supply and maintenance launches but
at this first cut it looks like a good bootstrapping strategy.
Doesn't it?

OK, I'm going with it, so I'm going to assume 25 launches to build
it and a maintenance/supply flight for every 20? launches. Thus
total launches are now

25 to build the rotovator
738 to build tower
37 to supply rotovator

Total 800 at $25 Million = $20 billion. Pretty damn good, huh. I
just shaved $44.5 Billion off of the project LOL :)))))

So now at 1 launch a day we're at 27 months of construction. Better.

Let's say the total cost of the project amounts to $30 Billion so as
to include carrying costs, administration, R&D, and other
incidentals.

Let's also say that the orbital hotel has a capacity for 932 guests.
Let's also assume that each guest, consumables and baggage masses at
225 kg.

If the Proton, or similar vehicle, becomes man rated, and we can
attach a passenger cabin how many people can we expect to launch?

Well if we can increase payload capacity by 400% to a suborbital
rendevous, then a Proton variant can launch 105,000 kg to an
altitude of 145 km. This means that 466 people, supplies etc can be
launched at once for $25 Million. That works out to be a ticket
price of $53,500, and a price of $238/kg.

If we assume a 3 day stay, then we have a yearly guest total at the
orbital hotel of 113,400. How much will they pay?

Let's say the $30 Billion is amortized over a 10 year period at a
rate of 18% then just the construction cost amounts to $57,200 per
guest. Factor in operating expenses (guests are already bring their
own consumables) and profit, so we charge the guests $146,500.

Total ticket price of $200,000 per person for a 3 day stay.

With a market of 113,400 passengers per year and a launch revenue of
$6.1 Billion, I'm sure aerospace companies will be interested in
developing a suborbital shuttle that can match the price/performance
of a Proton ( and be able to land the passengers back on Earth :)

Now we can also count on ancillary revenue. No longer will LEO and
GSO launches be competitive. Everything can go via the suborbital
route, dock with the tower, climb to the top and cast off with
rocket assist if necessary. How much revenue will this add? Also,
bootstrapping into other ventures is now more feasible because . . .

We've lowered the the launch cost to 20% of current market prices
without any new advances in technology! I've just decided that this
is going to be the title of this post.

Finished. What a way to spend a rainy afternoon.

Well, Thanks you TangoMan, you absolutely convinced me
that a tether can solve the problem. I hope someone
try it soon.

And, about Tango music. I asked you because I like it
too; my father used to sing it with his friends long
time ago. I don't know if you have noticed (for sure
you have), but my mother language is Spanish so, if
you want a translation for Tango lyrics, here I am to
help you; and it would be a pleasure to do it so. They
are just small volumens of phylosophy that the Tango
singers sing. If you have not as yet, try to find a
translation of "Cambalache".

Omar Vega

--- victoriatangoman wrote:
> --- In spacesettlers@yahoogroups.com, omar vega
> wrote:
>
> > Well, TangoMan, you may be right but I have some
> doubt
> > in the technical aspect of your proposal. If you
> have
> > two objets traveling in the same direction, one at
> > Mach 18 and the another at Mach 25, isn't there a
> > difference of Mach 7 between them? How it is going
> to
> > work? I'm just curious. Is there a Skyhook that
> could
> > resist the tension of the first impact?
>
> Two points;
>
> 1.) for a rotating tether, all we're really
> concerned with is the
> rendevouz velocity and the period of rendevouz. The
> rotating tether
> will release the payload at Mach 25 but it need not
> be traveling at
> that velocity.
>
> For a very detailed treatment of skyhooks go here:
> http://www.tethers.com/OrbitToOrbit.html
>
> 2.) for a stationary tether, the center on mass will
> have a velocity
> of Mach 25, but points below will allow docking at
> anywhere from 70%
> to 90% of orbital velocity (the longer the tower the
> lower the
> docking velocity.
>
> I'll attach a post from another group at the end of
> this message
> that I spent an afternoon developing.
>
> > why do you use the nickname "TangoMan". I
> > just wonder if you like Tango music, or if there
> is
> > another reason for that.
>
> Dancing is one of the most effective methods of
> insuring marital
> bliss! Years back it also allowed me to "punch above
> my weight
> class" in the dating world and later while my wife
> was in medical
> school, we really got deeply involved.
>
> I didn't think that these names quite had the same
> ring:
>
> FlamencoHombre
> JiveGuy
> ChaChaMan
> RumbaDude
> PasoDobleHombre
> SambaHomem
> WaltzMann
> FoxtrotStud
> VienneseWaltzGod
> QuickstepBoy
>
> Besides, Tango has a dramatic flair to the music and
> to the dance
> that I really enjoy. Argentine Tango is quite an
> intimate and flashy
> dance. I encourage all to participate (great women
> to men ratios for
> you single guys :)
>
> TangoMan
> ---------------
> Here's the other post I mentioned:
>
> Just thought I'd sit down and do a first order
> costing approximation
> on how to lower launch costs and see where it leads
> me. I haven't
> figured this out yet because I'm writing this as I
> go, so at the end
> this may all turn out to be an exercise in
> determining it can't
> work. Be warned that this'll probbly be an exercise
> of meaningless
> numbers coming to a conclusion.
>
> Space tourism seems to me to be a ready market if we
> can hit the
> right price points and generate enough volume. So
> how do we do it.
>
> I'm going to rely a lot on my notes which I've
> gathered from various
> sources with varying degrees of attribution. It's
> kind of a big
> jumble broken into topics.
>
> Let me break the question into two sceanrios:
> orbital and sub-
> orbital technology. I'll leave the orbital question
> for another time
> or for someone else.
>
> Suborbital obviously requires a secondary means to
> cover the
> remaining distance. I'm going to look into an
> orbiting tower. Here's
> the proposal.
>
> A 1,380 km long tower. Center of mass orbiting at
> 1,250 km, a
> docking station at 260 km, and a low gravity section
> at 1,640 km.
> From the docking station a winch is lowered to an
> altitude of 145 km
> to intersect with a shuttle and then pulls the
> shuttle up to the
> docking station.
>
> What to build this out of. Spectra 1000 has a
> tensile strength of
> 3.0 GPa and a density of 0.97 g/cc but the Van Allen
> radiation belts
> are going to make it pretty useless.
>
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=PCF007
>
> Spectra 2000 is an improvement.
>
http://www.spectrafiber.com/pdfs/hon-pf-ps10-sp2000.pdf
>
> While we're awaiting the perfection of carbon
> nanotubes, we can
> consider carbon fibers. Thornel Carbon Fiber T-40
> has a density of
> 1.81 g/cc and a tensile strength of 5.65 GPa.
>
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=ETHOR0

--- In spacesettlers@yahoogroups.com, omar vega wrote:

> Well, Thanks you TangoMan, you absolutely convinced me
> that a tether can solve the problem. I hope someone
> try it soon.

So do I! We should be building infrastructure in orbit rather than
going to the moon or to Mars. The infrastructure will be able to be
used to facilitate commerce which will lead to more and more
activity in orbit. Tethers will lead to docking requirements which
are easier to achieve. It makes so much sense to me, but I guess
tethers aren't as dramatic as rockets or space elevators.

> but my mother language is Spanish so, if
> you want a translation for Tango lyrics, here I am to
> help you;

Thank you for the offer. Is there much Flamenco near you? My
daughter and I are quite big into that right now (summer). The
cante, palmas and baile are quite fun and very dramatic. I seem to
be the only Flamenco Dad around though, but I do like my nail-soled
suede boots :) The rythyms are quite powerful too. The women are
quite dramatic in their long skirts and their castanuelas as they
perform solearas, alegrias, and fandangos. If it is near you, it
must be nice to have this flair and color so readily available.

TangoMan

Unfortunaltely not. Flamenco is a dance from Spain
that express the feeling of the Gypsies, who are a
minority there. Their plays remember dances and music
that date back to the time the arabs invaded Spain.
Is a beautiful music that both Spaniards and Latin
American enjoy very much, but that only a Gypsy can
dance with such a skill. By the way, you may try "Paco
de Lucia", the greatest Flamenco guitar player ever.

Nice to talk with you. Well, and if you which
translations of Flamenco, I'll do too. Say hi to your
family and keep dancing.

Omar Vega

--- victoriatangoman wrote:

From: andynimmo [mailto:ud@...]

> Recently the Space Elevator fans have been holding a conference and
> as a result, the subject came up at a discussion after a meeting of
> the Mars Society UK (Scotland). It was suggested that a Martian
> elevator ought to be combined with solar power satellites, then the
> idea moved to doing this with terrestrial elevators.

Well I should hope so. I hope the original proposal wasn't to build SPS
from Martian resources and then send them all the way back to Earth. If
so, I'd call it a classic example of starting with the desired location
first, and then casting about looking for an economic justification
second.

Even in the case of Phobos and Deimos, I don't think I would recommend
use of their resources except for products whose end use was in Mars
orbit.

But yeah, it's a shame that the Martian elevator is an easier job than
the Earth one when the Earth one is the one needed first.

> You could pipe
> power down the elevator cable thereby making solar power sats more
> environmentally acceptable, while at the same time making elevators
> even more economical as in addition to giving cheaper access to LEO
> their owners would be able to sell power.

I think it's no longer considered technically feasible to send
electrical power up and down space elevators. You might have noticed
that in the newer designs the elevator cars receive laser-beamed power.

I really wouldn't worry about trying to improve the environmental
acceptability of SPS power. Those power beams were studied pretty
extensively back in the 1970's, and they could find no plausible cause
for concern.

> Tourism to LEO is probably going to be the thing that really rings
> down the cost of getting up there, but the elevator is certainly one
> means of bring that within reach. What is the next stage though? How
> do we get from the LEO Hilton to the first real O'Neill type
> habitat? Any ideas?

If we go the space tourism route vs. the SPS route, the transition from
the LEO Hilton to Island One might be slow, incremental, and
evolutionary. But I think it would happen.

But in a space elevator world, placing mining equipment and a mass
driver on the moon, and ore refineries and manufacturing facilities in
HEO would be much cheaper than at present, or with any plausible
propulsion system. A person might go too far and argue that a space
elevator would make use of space resources unnecessary, but even a
fairly mature elevator wouldn't be able to quickly lift several million
tons. I think we would still see High Frontier-type development, just
greatly accelerated.

Regards,

Mike Combs

Hi Mike,

As there were a number of folk present and the subject came up during
general discussion after the meeting the whole thing began a bit
confusingly. When I made the suggestion re a terrestrial elevator,
Duncan mistook me to be talking about a Martian elevator and brought
in the Deimos comment. However, I do agree with Bob in an earlier
email, that getting it into the correct orbit would probably cost more
than it might be worth.

I have indeed noticed that in the newer designs the elevator cars
receive laser-beamed power, but there are reasons why that may not
prove practical. Re the point Bob made about the arithmetic re piping
power in the nanotubes in his email would depend on the electrical
resistance of carbon nanotubes, this would probably be varied by the
surrounding circumstances such as temperature and atmospheric pressure
variations at differing heights. No matter how complex though, if
piping was to be considered the problems would have to be solved.
Also, the initial elevator would have to be built substantially enough
to carry its own operating power. I'm not suggesting anything is easy,
but if these problems can be solved then the elevator can be operated
free of charge by sunpower and would make the additional profits from
sale of power on Earth. With laser-power you'd simply have an extra
cost and no extra profit.

Environmental accepability by scientists and spacefans is one thing,
but acceptability to politicians - particularly on the international
front is very definitely another. After the recent stramash in Moscow
where Sir David King attempted to silence critics of global warming on
behalf of the UK Government - then was shown the door by our Russian
friends, this should be obvious.

I do agree very much that with an elevator we would see High Frontier-
type development, greatly accelerated.

Best wishes, Andy Nimmo

>
> From: andynimmo [mailto:ud@...]
>
> > Recently the Space Elevator fans have been holding a conference
and
> > as a result, the subject came up at a discussion after a
meeting of
> > the Mars Society UK (Scotland). It was suggested that a Martian

> > elevator ought to be combined with solar power satellites, then
the
> > idea moved to doing this with terrestrial elevators.
>
> Well I should hope so. I hope the original proposal wasn't to
build SPS
> from Martian resources and then send them all the way back to
Earth. If
> so, I'd call it a classic example of starting with the desired
location
> first, and then casting about looking for an economic
justification
> second.
>
> Even in the case of Phobos and Deimos, I don't think I would
recommend
> use of their resources except for products whose end use was in
Mars
> orbit.
>
> But yeah, it's a shame that the Martian elevator is an easier job
than
> the Earth one when the Earth one is the one needed first.
>
> > You could pipe
> > power down the elevator cable thereby making solar power sats
more
> > environmentally acceptable, while at the same time making
elevators
> > even more economical as in addition to giving cheaper access to
LEO
> > their owners would be able to sell power.
>
> I think it's no longer considered technically feasible to send
> electrical power up and down space elevators. You might have
noticed
> that in the newer designs the elevator cars receive laser-beamed
power.
>
> I really wouldn't worry about trying to improve the environmental
> acceptability of SPS power. Those power beams were studied
pretty
> extensively back in the 1970's, and they could find no plausible
cause
> for concern.
>
> > Tourism to LEO is probably going to be the thing that really
rings
> > down the cost of getting up there, but the elevator is
certainly one
> > means of bring that within reach. What is the next stage
though? How
> > do we get from the LEO Hilton to the first real O'Neill type

> > habitat? Any ideas?
>
> If we go the space tourism route vs. the SPS route, the transition
from
> the LEO Hilton to Island One might be slow, incremental, and
> evolutionary. But I think it would happen.
>
> But in a space elevator world, placing mining equipment and a
mass
> driver on the moon, and ore refineries and manufacturing facilities
in
> HEO would be much cheaper than at present, or with any plausible
> propulsion system. A person might go too far and argue that a
space
> elevator would make use of space resources unnecessary, but even
a
> fairly mature elevator wouldn't be able to quickly lift several
million
> tons. I think we would still see High Frontier-type
development, just
> greatly accelerated.
>
> Regards,
>
> Mike Combs
>
Sponsor
>
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