> From: Steve Long [mailto:longsteven@...]
> Rather than focus on the end product, maybe we should as a first step
> consider exerting our intellectual efforts on how to cheaply get large
> masses of payload into orbit? If we're in a hurry, I think we should
> forget about cutting-edge technology like Scramjets and the like, and
> just resurrect the Saturn-5 booster as a Saturn-7 or something,
the shuttle aay from the STS, and leave the engines behind, and you can
launch a hundred tons into orbit. Include the tank and that jumps to
130tons. If you junk the shuttle (with it's extensive refurbishment process,
and heavily restrictive flight conditions) and you could launch much more
often. Simply doing that would reduce costs by a factor of 5-10. But it only
works if you're launching a lot, and it's politically difficult for NASA to
admit anything could be better to the shuttle.
Largest launch vehicle ever seriously proposed was Sea Dragon. This was a
'build it big and it gets cheap' design capable of putting 500tons at a time
into orbit. Designed to be built at a shipyard out of boiler-plate
technology (I kidd ye not!) and towed out to sea by a semi-decomissioned
nuclear aircraft carrier, which would then electrolise the sea for fuel.
John
Never too early to start planning.
problem.
One way could be to have one parent company with the overall goal, set up
two sub companies to deal with each part of the problem.
Company 1 designs and builds the launch systems - say a Sea Dragon type -
500 tons to orbit.
Company 2 designs and builds the SPS.
Target investors for each company individually who would be interested in
that area (some may be interested in both).
Point out that the launch systems will have a ready made market for
Company 1.
For Company 2 point out that there will be adequate launch facilities. At
a cost which should be able to be fairly reliably worked out, given that
you know how many launches you need and company 1 will be able to provide
the cost to build for x number of launches.
Note company 1 does not build man rated systems only the delivery vehicle.
So you would either have to have another company to build a man rated
vehicle on a small scale that is just a bus, or you contract it out to
someone else.
Once you start lifting 500 tons per shot, no doubt a few people will be
interested in building a bus to get people up there.
having the ready made market for the launch system will allow it to prove
itself, and get people thinking of what they can do with all that launch
space.
Just an idea.
Brett
Steve Wrote:
--- In spacesettlers@yahoogroups.com, "victoriatangoman"
wrote:
>
> --- In spacesettlers@yahoogroups.com, "Richard" wrote:
>
> > I feel that to do a decent job of researching even a small world
> > like Mars, we will need to have some sort of support structure to
> > feed, house, and clothe the researchers. Not to mention
> > transportation.
>
> OK, being very careful to not read into your comments anything beyond
> what you've written. LOL :)
>
> I see your reference to researching Mars. I have no issues with that.
> What do you mean by support structure? I would think that the housing
> and clothes would be sent from Earth. The food would be grown locally
> but with many of the implements also sent from Earth. Do you disagree?
>
> The alternative is to source them locally. To grow cotton, let's say,
> then someone, or some machine, has to pick it. Then it has to be
> prepared in a cotton mill. Then woven into fabric. Then cut into
> clothes. This seems like an awfully complex and *mass intensive* (mass
> coming from Earth) process all in order to support a research community.
Why cotton? Why not synthetics?
>
> > A lot of territory to cover. And by the time it has been
> > researched, there will probably be people who have lived there most
> > of their life.
>
> Seeing how these researchers are sent up there on the taxpayer's dime
> don't you think that there would be Earthside clamoring from other
> scientists who also want a go at a Mars mission. For some scientists
> to stay there for their whole lives would foreclose the opportunity
> for other, and perhaps younger, scientists.
>
Scientist have to eat. They need transportation. Not to mention
clothes, housing, etc. You are forgotting all the support personnel.
> Darn, the oldsters got there first, when I was still in grade school
> and couldn't compete for a slot. Now it's 20 years later and I'm a
> promising young researcher and I need to be on Mars to test my
> hypothesis, but they want me to write a research plan and radio it to
> the scientists on Mars to conduct. Those old fossils, and I don't mean
> the indiginous variety either, are still on Mars and with them there
> doing the work, they don't need me. I better call my Congressman or UN
> delegate or whatever, and complain.
>
Now Tangoman. Take three deep breaths and try to compose yourself.
Don't want you going off the deep end again.
> > By the time Mars is totally checked out, it will probably have a
> > permenant population.
>
> This I don't see, unless that research population grows to such a
> size, that some beancounters decide that it'll make more sense to ship
> up a cotton mill, steel foundry, and other industrial equipment,
> rather than simply provide the supplies.
>
This depends on costs. It may be cheaper tp ship stuff from the
Asteroid Belt or Luna.
> I don't see the leap from research station and personnel to a
> permanent population. Can you break it down in baby steps for me? No,
> honestly, I'm not being facetious here.
>
I still think that on a world so far from Earth, you are going to need
plenty of support personnel. Scientist are going to be too busy to
put up housing, grow food, provide fuel for a transportation system
(Mars is a big place), etc.
> > Incidentally while we cannot build a beanstalk from the Earth's
> > surface to geosynchonous orbit today, I've read that one could be
> > built on Mars using current strength of materials.
>
> Yes, the engineering is definitely more plausible, but *why* would we
> want to?
>
You talk about supplying the material for an in-depth survey of an
entire world. Just think of all the rocket fuel it would take. A
Beanstalk would save a lot of money.
> > Mars being closer than most asteroids, would mean that it could
> > supply material (even ores) as cheaply as the asteroid belt.
> >
> > Rick Brooks
>
> Closer how, in kilometers, or in delta-v? Delta-v is the metric we
> need to look at. Your statement also doesn't account for access to
> NEOs that are closer in, in both km and delta-v, than Mars.
>
> TangoMan
Delta-v is what counts here.
Are there really that many NEOs?
Mars many also be a useful stepping stone to colonizing the Asteroid
Belt. And suppling material for the same.
Rick Brooks
Richard wrote:
>
> Delta-v is what counts here.
>
> Are there really that many NEOs?
>
http://neo.jpl.nasa.gov/stats/
there are currently about 3000 known NEOs, of which about 735 are 1 km in
diameter or larger. I can't quickly locate any info on the composition of
these bodies. Some will be asteroidal, others will be comet fragments or
burned-out cometary nuclei.
NASA is on a ten-year project to locate and orbit-plot 90% of all NEOs.
I've got no idea what percentage of the total the two numbers I've provided comprises.
Steve
--- In spacesettlers@yahoogroups.com, "Michael Capriola"
wrote:
> "victoriatangoman" wrote:
>
>
> be the limiting factor.>
>
> Well, of course.
> As I've said, the number and capacity of habitats will be built
based on
> need.
>
> To answer some of your other questions, I don't think they'll put a
halt on
> immigration. If it looks like there's a steady influx of new people,
> they'll start construction on new habitats beforehand. Supply and
Demand --
> it looks like people need new housing, so we build new housing.
>
> The 10-million person habitat: Yeah, O'Neil was trying to impress
people
> with just how large this things could be, but we've forgotten that
we'd need
> TWO cylinders linked at the 'poles' and rotating in different
directions to
> counter torque effects. Now we're talking a city of 20 million in
paired
> cylinders. Don't expect to see one built even in my grandchildren's
time.
> ;)
>
> And no, I doubt we'll built a 10,000 person habitat to hold a mere
500.
> Unless, of course, it looks likely to be filled up within a certain
time
> period.
>
>> of time it takes to replicate the Habitat shell itself. So if it take[s]
> 10 years to build a Habitat, of whatever size, then plan on taking 10
> years to fill up the first Habitat. A planned growth so to speak.>
>
> This is where the Planning Commission is going to have headaches and
ulcers.
> ;) Here on Earth, overcrowding can be dealt with by building
new houses
> in the suburbs within a short period of time. In space, you'd have
to build
> a whole new habitat ahead of time.
>
> We might start out with a bunch of 'villages' of 1000-person
capacity with
> 50% actual occupancy, and as they fill up, we'd start to think about
> building that 10,000-person habitat. And then another. By the
time you
> have a dozen or so of those filling up, then you think about an even
larger
> habitat that is going to be settled by the overflow from all the 10,000
> capacity towns. The small, 1000-capacity 'villages' might even be
abandoned
> at some point as being too old and expensive to maintain. Or people
might
> live there temporarily while they wait for a chance to move to a
bigger and
> better habitat.
>
> Again, the Planning Commission is going to need very accurate
forecasts of
> population growth in order to know when to start new habitat
construction
> and where.
>
> And you raise an interesting question: Just how long will it take
to build
> a habitat of N-capacity?
>
> Anyone have an answer to that question?
Certainly. After some have been completely built, we should be able
to estimate.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Richard [mailto:rabrooks@g...]
>
> > > What riches are there to be made on Mars? None.
> > >
> > All right, I've heard enough. You say None. Prove it.
>
> You're asking him to prove a negative, which is notoriously difficult.
> It's up to the Mars enthusiast to at least point to a somewhat plausible
> positive.
>
> Regards,
>
> Mike Combs
I'm not a Mars enthusiast.
I merely have been opposing absolutist statements.
After we been on Mars for about fifty years, We should have some
answers. A pity I won't be here to see it. But somehow living to 113
seems unduly optimistic.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Richard [mailto:rabrooks@g...]
>
> > No. I have no faith that we will find anything.
> > But we should go and take a look.
>
> Most of us on this list are very much in favor of going to have a look.
>
> > To set Mars off limits strikes me as silly.
>
> I don't think anybody is trying to set Mars "off limits". We're just
> listing possible reasons for expecting that things on Mars will not go
> much beyond government-funded exploration for planetary science. Or
> somewhat more generously, reasons for suspecting Mars settlements would
> have a great deal of difficulty competing economically with orbital
> settlements.
>
> Regards,
>
> Mike Combs
I like science fiction. Blue-skying is fun. But I'm afraid some
people are taking this thing too seriously.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Steve Long [mailto:longsteven@c...]
>
> > victoriatangoman wrote:
> > >
> > > Mars is a religion for a lot of these folks, and nothing will shake
> > > their faith.
> > >
> > I respectfully submit this question to the group: In
> > the most-recent series of exchanges, which responder
> > seems most religiously fervent about their beliefs?
>
> I won't address the issue of who is most "fervent", but I note that
> tangoman invited you to discuss what you saw as the specific advantages
> of Mars over orbital settlements, and you begged off, citing lack of
> information. These seems to make your position one based on faith.
>
Faith? Ruling out a whole world without taking a look!
I say there may be something on Mars. Hardly seems like faith to me.
> I, too, have found in my debates with Mars advocates that after I list
> my (actually, Gerry's) detailed points regarding what I see as the
> advantages of orbital locations over planetary ones, and invite the
> inverse, the Mars advocate begs off. I've heard everything from, "I can
> but I won't," to "I don't have the time," to "I won't because you still
> won't believe me after I've put all that effort into it".
>
> Regards,
>
> Mike Combs
Well, Mike, I think the asteroids are better than Mars. So why should
I put much effort into defending Mars?
I wouldn't ended up defending it except for Tangoman saying it was
worthless on very insufficient data.
Rick Brooks
--- In spacesettlers@yahoogroups.com, Steve Long wrote:
>
> "Combs, Mike" wrote:
> >
> > From: Richard [mailto:rabrooks@g...]
> >
> > > > What riches are there to be made on Mars? None.
> > > >
> > > All right, I've heard enough. You say None. Prove it.
> >
> > You're asking him to prove a negative, which is notoriously
> > difficult.
> > It's up to the Mars enthusiast to at least point to a somewhat
> > plausible
> > positive.
> >
> ::: tossing up an idea ::: Many precious stones are a side-effect of
> vulcanism. deBeers might find something interesting to do under
> Olympus Mons.
>
> Steve
planetary environment to form.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Richard [mailto:rabrooks@g...]
>
> > Mars being in beween the Earth and the Moon in both
> > gravity and atmosphere may have its own ores.
> >
> > I feel that it is the height of stupidity not to go and take a look.
>
> As the evidence for a wet past for Mars grows, I'd say we are far more
> likely to find differentiated ores on Mars than on the moon. But lunar
> "ores" (just plain dirt, really) are still more economically valuable.
> Why? Two reasons:
>
> 1. They are at the bottom of a much shallower gravity well, which means
> exportation costs will be lower.
>
> 2. They are much closer to the only plausible market in the near-term:
> orbital spaces near Earth.
>
> Regards,
>
> Mike Combs
almost certainly not near-term.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Steve Long [mailto:longsteven@c...]
>
> > We're both dealing with fantasy, here. Neither Mars
> > colonies or space habitats exist at this time. We're
> > all blue-skying.
>
> I would argue that a fantasy with a proposed (if theoretical) business
> plan is at least one notch up from one with no business plan at all.
>
> > Neither your fantasy nor anyone else's is better.
>
> If we try to bring real-life physics, technology, and economics to our
> fantasies, we might can bring our dreams to reality. But not if we're
> only 2-for-3. And if we make our comparisons on the basis of physics,
> technology, and economics (as opposed to tastes or convictions) then
> yes, we can make some relative value judgments which have a degree of
> objectivity to them.
>
> > And just as I send itinerant preachers selling exhortations
> > away from my door, I will no longer respond to what this
> > thread has become. Your certainty will never overcome my
> > uncertainty, nor will I attempt to open your mind. I have
> > no interest in spreading doubt among the born-again.
> > There are other things going on in my life, and preaching
> > against preaching takes too much time and energy.
>
> I invite you to continue the discussion with me, and I'll promise never
> to use NAMBLA nor NAZIs for points of comparison (and in any case, the
> latter, in accordance with Godwin's law, ends the debate).
>
> But I beg you to engage in a bit of honest introspection. Is your
> desire to extricate yourself from this debate motivated entirely and
> solely from having taken offence? Or might at least a tiny part of it
> be that you know you can't refute some of the point raised here?
>
> Regards,
>
> Mike Combs
know until we've had space experience on building in space.
I still think that we are being premature.
It's fun to specualate and set out the possibilities. But I feel,
that at this stage, it is foolish to close out any possibilities.
Rick Brooks
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
> From: Richard [mailto:rabrooks@g...]
>
> > Mars being closer than most asteroids, would mean that
> > it could supply material (even ores) as cheaply as the
> > asteroid belt.
>
> The expense is not an issue of proximity, it's primarily an issue of
> delta-V. From a delta-V point of view, the surface of Mars is "further
> away" because it's at the bottom of a relatively steep gravity well.
>
How about a solar powered O'Neill type mass driver?
--- In spacesettlers@yahoogroups.com, "Richard" wrote:
Then you must be one annoyed guy. If your banker tells you you don't
have any money in your account, could he possibly mean that you
actually do have money?
There are absolutes in the world, and yes, there are absolutes even
for situations of imagination.
We know that Mars has a gravity well and Habitats don't. There's no
way around that. That's absolute. You can't escape the physics of this
situation no matter how long you explore Mars.
Mars has gravity. Habitats don't. That's absolute.
Cislunar space is closer to Earth than is Mars. That's absolute.
Exploring Mars for a thousand years won't change that.
It takes less energy to a kilo into GEO, L5, LIO, and to land on the
Moon than it does for MIO, or to land on Mars. That's absolute.
Items or services in orbit are closer to Earth than similar items or
services on Mars. Again absolute.
Gee, I hope I'm not ruining your day with these absolutes.
We don't need to construct a Habitat and develop a base on Mars to
know the above to be truly absolute. These aren't matters that need
experimental proof.
Mars will be composed of the same elements as those found on Earth.
The minerals that result may be different than those found on Earth
due to differing geologic processes. Those geologic processes involve
heat and pressure. These processes can be duplicated on Earth. I know
this because I've done it. I've made sapphires and emeralds in a
labortory and needed heat and pressure to achieve the result.
It's too bad you don't like absolute statements. Everything I've
written is supportable.
> I merely have been opposing absolutist statements.
To what end? What purpose does it serve to call day night, when
everyone makes the absolutist statement that day is day and night is
night.
> After we been on Mars for about fifty years, We should have some
> answers.
After 50 years will Mars no longer be at the bottom of a gravity well?
Will it be closer to Earth? Will transport to Mars require less energy
than it does today?
I've never written that Mars shouldn't be explored. I simply written
that it doesn't make sense to base a civilization there. Explore for
50 years or for 500 years and it won't change the absolute physical
facts. Sorry to be breaking this news to you.
TangoMan
--- In spacesettlers@yahoogroups.com, "victoriatangoman"
wrote:
>
> --- In spacesettlers@yahoogroups.com, "Richard" wrote:
>
> > Quite right. But people who use words like all and none annoy me.
>
> Then you must be one annoyed guy. If your banker tells you you don't
> have any money in your account, could he possibly mean that you
> actually do have money?
>
> There are absolutes in the world, and yes, there are absolutes even
> for situations of imagination.
>
> We know that Mars has a gravity well and Habitats don't. There's no
> way around that. That's absolute. You can't escape the physics of this
> situation no matter how long you explore Mars.
>
> Mars has gravity. Habitats don't. That's absolute.
>
> Cislunar space is closer to Earth than is Mars. That's absolute.
> Exploring Mars for a thousand years won't change that.
>
> It takes less energy to a kilo into GEO, L5, LIO, and to land on the
> Moon than it does for MIO, or to land on Mars. That's absolute.
>
> Items or services in orbit are closer to Earth than similar items or
> services on Mars. Again absolute.
>
> Gee, I hope I'm not ruining your day with these absolutes.
>
> We don't need to construct a Habitat and develop a base on Mars to
> know the above to be truly absolute. These aren't matters that need
> experimental proof.
>
> Mars will be composed of the same elements as those found on Earth.
> The minerals that result may be different than those found on Earth
> due to differing geologic processes. Those geologic processes involve
> heat and pressure. These processes can be duplicated on Earth. I know
> this because I've done it. I've made sapphires and emeralds in a
> labortory and needed heat and pressure to achieve the result.
>
> It's too bad you don't like absolute statements. Everything I've
> written is supportable.
>
> > I merely have been opposing absolutist statements.
>
> To what end? What purpose does it serve to call day night, when
> everyone makes the absolutist statement that day is day and night is
> night.
>
> > After we been on Mars for about fifty years, We should have some
> > answers.
>
> After 50 years will Mars no longer be at the bottom of a gravity well?
> Will it be closer to Earth? Will transport to Mars require less energy
> than it does today?
>
> I've never written that Mars shouldn't be explored. I simply written
> that it doesn't make sense to base a civilization there. Explore for
> 50 years or for 500 years and it won't change the absolute physical
> facts. Sorry to be breaking this news to you.
>
> TangoMan
You forget that I don't take you seriously. I've heard anti-space
rants since before you were born. I should ignore them by now.
I really should have quit answering you before. You get more rigid
and more rhetorical. You don't take kindly to people who disagree
with you.
A pity as I thought before you had some interesting speculations.
Rick Brooks
"victoriatangoman" wrote:
It might. I read somewhere that they no longer believe it's going to take
as long as 2 years to get to Mars; we might be able to do it in 6 to 8
months. If I get a chance, I'll see if I can find some verification for
this.
Offhand, I agree with you, but one never knows. Five hundred years from now
it might just make sense to base a civilization on Mars for whatever reason.
There was a novel, "Memory of Whiteness" (I forget the author), in which
Mars had temporarily -- temporarily, mind you -- become the major trade
nexus of the solar system due to the positions of the planets and major
asteroids at the time.
From: Steve Long [mailto:longsteven@...]
> a side-effect of vulcanism. deBeers might find
> something interesting to do under Olympus Mons.
As soon as we learn that such Martian jewels exist, they can enter the
discussion. Until then, they really shouldn't.
Let me put it this way. If Gerard O'Neill has proposed orbital
habitats, and then when asked what the settlers would be doing for a
living, said, "Gee, I dunno, maybe there are diamonds floating around in
HEO that they could go out, scoop up, and sell," what would the reaction
have been?
Regards,
Mike Combs
From: Steve Long [mailto:longsteven@...]
> instance? We can barely get supplies up to an existing
> orbital station to keep two astronauts alive and healthy.
> How are we going to get a few aircraft-carrier-equivalents
> of construction materials and consumables and a crew to
> assemble it all into space if we can't even do that?
It can't be denied that we've got to get there from here, nor that
"here" is a long ways away from where we need to be.
> Rather than focus on the end product, maybe we should as
> a first step consider exerting our intellectual efforts on
> how to cheaply get large masses of payload into orbit?
I get this a lot. Someone talks about permanent human settlements on
Mars. I propose permanent human settlements in orbit as an alternative.
Then I get told I'm a pie-in-the-sky dreamer because first we have to
think about CATS. But if our present lack of CATS makes discussions of
High Frontier premature (and I can see and respect that point of view),
why does it not also make discussions of permanent human settlements on
Mars premature?
I think one point we can all agree on is that if person "A" is talking
about reducing the cost for a pound to orbit, person "B" is talking
about High Frontier with SPS as the business plan, and person "C" is
talking about Mars settlements, person "A" is discussing the most
near-term and critical issue. I can see the argument that he's the most
practical, attacking the immediate problem. But persons "B" and "C" are
equally-far-out in terms of their projections, and the only distinction
between them is that person "B" is trying to work inside the
requirements of economics while "C" is leaving that out of his
projections.
But then we have person "D" who doesn't think space travel is going to
amount to anything until we have interstellar travel based on FTL
drives. So while "A" may rightly criticize "B" and "C" for getting
ahead of themselves, they're still not the worst offenders around. :)
Regards,
Mike Combs
--- In spacesettlers, "victoriatangoman" wrote:
> well?
Well of course Mars will still be at the bottom of a gravity well.
> Will it be closer to Earth?
I rather doubt it.
> Will transport to Mars require less energy than it does today?
Yes. Today when we send something to Mars, a lot of energy is
wasted. 50 years from now, we should have a more efficient way of
doing the transport thing. Not to mention that, with SPS (because we
have habitats) there should be more energy available to work with.
Laser-pushed light sails, anybody?
From: Richard [mailto:rabrooks@...]
>
> I'm not a Mars enthusiast.
>
> I merely have been opposing absolutist statements.
It's true that absolutist statements should be avoided because they are
almost always wrong. It rankles us O'Neillians when we hear dogmatic
statements like "nobody will ever settle HEO", but we shouldn't respond
in kind. For myself, I try to never say that nobody will ever live on
Mars. If it ever gets cheap enough, some may choose to live there for
no other reason than a personal love of the planet. To me, it's enough
to say that the markets for Mars are presently unidentified, or to list
reasons why a settlement on Mars might have difficulty competing
economically with one in orbit.
Regards,
Mike Combs
From: Richard [mailto:rabrooks@...]
>
> I'd say that Tangoman is the one running on faith. Mars is worthless.
Tangoman does not have "faith that Mars is worthless". He is being a
skeptic. A skeptic is not someone who believes in a negative, but one
who reserves judgment on a positive until evidence is in.
A skeptic is willing to change his position if better evidence arrives.
If Spirit or Opportunity discover dilithium crystals on Mars tomorrow,
and we don't change our position, then there's something wrong with us.
But in the meanwhile, we don't see anything wrong with suggesting that
purely hypotheticals should be left out of a serious conversation.
> I say there may be something on Mars. Hardly seems like faith to me.
But anyone who foresees the colonization of Mars is basing it on the
faith that "something" will come up later. You say you're not
particularly a Mars enthusiast, so maybe that's not you. But they're
out there. And Tangoman is hardly exaggerating when he says that it has
become a religious belief for some. And their treatment of O'Neill's
work resembles the devout's treatment of heresy.
> Well, Mike, I think the asteroids are better than Mars.
> So why should I put much effort into defending Mars?
That's common ground between us. In the near-term, I certainly expect
the first generation of space habitats to be built in HEO. But in the
long term, I expect far more will be built in the Belt, to the point
where the population in the Belt exceeds both that on Earth and around
it.
Regards,
Mike Combs
>
> But if our present lack of CATS makes discussions of
> High Frontier premature (and I can see and respect that point of view),
> why does it not also make discussions of permanent human settlements on
> Mars premature?
>
expletives are not, at this point.
Steve
From: Richard [mailto:rabrooks@...]
The problem with any mass driver set up on the surface of a planet with
an atmosphere is that the payloads are like meteors in reverse (worse,
actually). On the other hand, the thickest part of the Martian
atmosphere is only about 1% as thick as what we're breathing right now.
And there are these enormous volcanoes not too terribly far from the
equator...
I'd go as far as saying a ground-based mass-driver launcher for Mars is
probably an easier proposition than same for Earth. But I'm still not
sure that would tip the balance away from NEOs toward Mars. The best
solution to pulling resources out of gravity wells is to pick extremely
shallow ones. The kind of thinking that persists in basing operations
on Mars tends to proceed from the assumption that human beings can only
be properly sustained on a planetary surface, but I don't agree with
that assumption.
Regards,
Mike Combs
"Combs, Mike" wrote:
>
> The problem with any mass driver set up on the surface of a planet with
> an atmosphere is that the payloads are like meteors in reverse (worse,
> actually). On the other hand, the thickest part of the Martian
> atmosphere is only about 1% as thick as what we're breathing right now.
> And there are these enormous volcanoes not too terribly far from the
> equator...
>
Martian atmosphere even at 10 millibars or so, is most likely way too thick
to launch through.
> I'd go as far as saying a ground-based mass-driver launcher for Mars is
> probably an easier proposition than same for Earth. But I'm still not
> sure that would tip the balance away from NEOs toward Mars. The best
> solution to pulling resources out of gravity wells is to pick extremely
> shallow ones. The kind of thinking that persists in basing operations
> on Mars tends to proceed from the assumption that human beings can only
> be properly sustained on a planetary surface, but I don't agree with
> that assumption.
>
A thought, from a neutral thinker (?) on these subjects: Since they're now
pretty certain that there is copious water below the Mars surface, which
can be electrolized into rocket fuel, does not having to carry return fuel
to the Mars surface help the equation any?
Steve
>A thought, from a neutral thinker (?) on these subjects: Since they're now
>pretty certain that there is copious water below the Mars surface, which
>can be electrolized into rocket fuel, does not having to carry return fuel
>to the Mars surface help the equation any?
subsurface water yet, but I haven't been following the rover findings that
closely), I'd point out that the Zubrin updates to the 1991 NASA Design
Reference Mission postulate that the only raw material necessary to bring to
Mars is hydrogen. The nuclear powered robot factories that would land on
Mars prior to the human mission would use the atmosphere and the hydrogen to
make 1) Oxygen for breathing, 2) water, and 3) methane, which along with O2
would be the propellant for the return trip. This plan is the essence of
the In-Situ Resource Utilization model, which (whatever else you can say
about Zubrin) is pretty darn elegant in its efficiency.
If indeed water is found in large quantities, the hydrogen supply issue is
largely solved, and even less mass would have to be carried from Earth.
Except that desalination, eletrolysis and compressed gas storage are all
fairly technology-intensive processes, requiring heavy equipment, many large
storage tanks, and lots of energy.
--- In spacesettlers@yahoogroups.com, "Xenophile"
> Yes. Today when we send something to Mars, a lot of energy is
> wasted. 50 years from now, we should have a more efficient way of
> doing the transport thing.
For all of those who caught the incongruity of an engineering
(propulsion system) claim amongst the physical constants (distance,
etc) I apologize for my sloppy phrasing. What I meant to write was
*kinetic energy* of transport to Mars, thus keeping to the theme of
physical absolutes.
An engineering breakthourgh which reduces total energy expended to
reach Mars by using a more efficient means of propulsion wouldn't
benefit strictly to Mars but to many space enterprises.
TangoMan