I wonder whether we are jumping the gun. Going into space is after all not like taking a stroll in your backyard. Once we leave the protection of our ecosphere we are faced with an intensely hostile environment. If the intention is to walk on Mars and come back, as was done in the case of the Moon there should be no major problem. But is that the aim of a trip to Mars? Or is it going to be something more durable, like setting up a small colony there?

With all the delta V's we are talking about, it is clear that supplying any outpost from Earth is going to be a very difficult task. The only way out is to make any space outpost basically self-sufficient in terms of basic needs; at this point in time the issue is not trade but SURVIVAL. And the only way to ensure it is to develop the technology so that a space settlement can almost fully recycle their supply of water and grow all the food required for survival. At the same time have the type of environment where everyone does not go nuts.

So the first step should be... Set up Space Habitats in Earth orbit where the required technologies can be proven. A couple of individuals should be able to stay in an enclosed environment for say two years, fully recycling all the water and growing all the fresh food they need - canned food should be kept to a minimum. Let us also do away with this zero G business. When zero G is known to be detrimental why deliberately persist with it?

In parallel... It will be desirable if nuclear rocket technology can be developed, which can use any matter as reaction fuel. This will make sure that rocketry is not dependent just on water as source for fuel

Does it sound crazy?

Selvaraj.

> From: sraj [mailto:sraj@...]
> With all the delta V's we are talking about, it is clear that
> supplying any outpost from Earth is going to be a very
> difficult task.

DeltaV is not the problem, it's cost. So it's really a case of making the coutposts as self-sufficient as possible and/or drastically reducing launch costs.

> When zero G is known to be detrimental why
> deliberately persist with it?

Zero-g is studied because it's effects are similar to certian bone diseases, and studying one may lead to cures for the other. NASA therefore designs its shuttles and stations to be zero-G enviroments. In earth orbit, thisd makes sense. On a multi-month trip to mars it's bloody stupid, but NASA lacks the experience to build anything else. And to the best of my knowledge, until recently they were restricted to pure-research, and literally were not legally permitted to put money into any colonisation effort.

ANTIcarrot.

How about sending robots to the moon? It's not like a few solar panels
won't come in handy and it's not as far as mars, so sending them
commands won't take 48 hours.

Properly equiped robots could start mining, and then build a structure.
Rock and Frozen water are both present on the moon, in my mind that
means that you can make concrete.

If you have concrete, your can build a few basic structures (at least,
for the robots) Now granted that I have no idea how concrete would
solidify in a freezing and vacuum environment, I'm just thinking and
inviting opinions.

My main point is: why not send a few robots first and building something
there. Once that's done, you could have something much more prepared for
a visit.

Somehow, I don't think that the next time that these people visit the
moon it'll be to focus on bringing back some rocks, I would leave some
equipement behind, perhaps like a micro-manufacture to build a few
things. There's metal on the moon, isn't there?

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: ANTIcarrot [mailto:dante.feditech@...]
Sent: Sunday, March 14, 2004 1:20 PM
To: spacesettlers@yahoogroups.com
Subject: RE: [spacesettlers] Jumping the Gun.

> From: sraj [mailto:sraj@...]
> With all the delta V's we are talking about, it is clear that
> supplying any outpost from Earth is going to be a very
> difficult task.

DeltaV is not the problem, it's cost. So it's really a case of making
the coutposts as self-sufficient as possible and/or drastically reducing
launch costs.

> When zero G is known to be detrimental why
> deliberately persist with it?

Zero-g is studied because it's effects are similar to certian bone
diseases, and studying one may lead to cures for the other. NASA
therefore designs its shuttles and stations to be zero-G enviroments. In
earth orbit, thisd makes sense. On a multi-month trip to mars it's
bloody stupid, but NASA lacks the experience to build anything else. And
to the best of my knowledge, until recently they were restricted to
pure-research, and literally were not legally permitted to put money
into any colonisation effort.

ANTIcarrot.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> How about sending robots to the moon? It's not like a few solar
panels
> won't come in handy and it's not as far as mars, so sending them
> commands won't take 48 hours.

Good idea.

Do you have anything to add to this post?

> If you have concrete, your can build a few basic structures (at
least,
> for the robots) Now granted that I have no idea how concrete would
> solidify in a freezing and vacuum environment, I'm just thinking
and
> inviting opinions.

Look here for a paper on lunar concrete:

http://f3.grp.yahoofs.com/v1/IA5VQPxWybEpg1xtyQHHmAQgEM_p-
J9z7obzPNwVVWrPFdYEQWySWfb-a9AEdPczn-
gK5MPqqLsriGlqxytcno6c9xAAlxcwAKp2FuuO/Concrete%20for%20Lunar%20Base%
20Construction.pdf

TangoMan

TangoMan, you are gold, let me check those links out

Karell Ste-Marie
C.I.O. - BrainBank Inc.
From: victoriatangoman [mailto:tango_dancer@...]
Sent: Sunday, March 14, 2004 9:51 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Jumping the Gun.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> How about sending robots to the moon? It's not like a few solar
panels
> won't come in handy and it's not as far as mars, so sending them
> commands won't take 48 hours.

Good idea.

Do you have anything to add to this post?

> If you have concrete, your can build a few basic structures (at
least,
> for the robots) Now granted that I have no idea how concrete would
> solidify in a freezing and vacuum environment, I'm just thinking
and
> inviting opinions.

Look here for a paper on lunar concrete:

http://f3.grp.yahoofs.com/v1/IA5VQPxWybEpg1xtyQHHmAQgEM_p-
J9z7obzPNwVVWrPFdYEQWySWfb-a9AEdPczn-
gK5MPqqLsriGlqxytcno6c9xAAlxcwAKp2FuuO/Concrete%20for%20Lunar%20Base%
20Construction.pdf

TangoMan

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> TangoMan, you are gold, let me check those links out

You might want to look at points 5, 16, 24 in the post.

TangoMan

Good suggestion, Karell Ste-Marie.

Remote operated equipment and robotics is what I want to have with
asteroid mining and this can be done with the moon as well.

No one one needs to set foot on either moons or asteroids.. all of
it can be done from space.

You still have humans close enough too in case of a malfunction or a
need to upgrade the hardware. EVA's and any landings/excursions
would be rare.

With asteroids, I was thinking of following the rocks orbital path
and remote operating the mining equipment.

I'm dying to see that lunar concrete pdf file, but can't get to it, mind
sending me the file directly (if possible), I would really appreciate
it.

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: victoriatangoman [mailto:tango_dancer@...]
Sent: Sunday, March 14, 2004 9:51 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Jumping the Gun.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> How about sending robots to the moon? It's not like a few solar
panels
> won't come in handy and it's not as far as mars, so sending them
> commands won't take 48 hours.

Good idea.

Do you have anything to add to this post?

> If you have concrete, your can build a few basic structures (at
least,
> for the robots) Now granted that I have no idea how concrete would
> solidify in a freezing and vacuum environment, I'm just thinking
and
> inviting opinions.

Look here for a paper on lunar concrete:

http://f3.grp.yahoofs.com/v1/IA5VQPxWybEpg1xtyQHHmAQgEM_p-
J9z7obzPNwVVWrPFdYEQWySWfb-a9AEdPczn-
gK5MPqqLsriGlqxytcno6c9xAAlxcwAKp2FuuO/Concrete%20for%20Lunar%20Base%
20Construction.pdf

TangoMan

Tangoman,

I did take a look at the post, I must commend you on the fact that it
seems to be quite complete and thought out (I'm not an expert, if it's
not accurate, it's fooling me).

I've always been of the mind that robots where the key to space travel
and colonization, humans need far too many things with them and also
need to come back. All of these factors raise costs - a robot doesn't
care if it doesn't come back and can have it's software completely
upgraded over a transmission from earth.

Nobody would cry if a robot was lost either, well, let's just say that
there wouldn't be a national holiday created over it. People would only
cry over the money spent.

I read most of the document (after your sent it over to me) and was
quite surprised to see the base though that I had in much more details.

I do wish to add a few ideas,

First, if we are going to conquer the stars, we need to think of other
methods of getting there and chemical propellant is not the trick. I
would rather create a small, portable, nuclear reactor to power the
craft from an atmospheric side of things and then use an ion drive in
space than use chemical propellant. It would reduce the cost so much
that it would basically pay for the research for getting the technology
created. So the initial ship costs as much to send to space because of
that, the other ones would cost significantly less because of the new
technology.

Once in space (or on the moon, or mars, whatever) you then have a
nuclear reactor that you can remove from the ship and use to power the
installation and possibly some robots. People won't really care about a
meltdown on the moon if things go really wrong, and that would only mean
in the eventuallity that the reactor can't be shutdown by safeguards nor
manually.

Water? Plenty of water on the moon (I *assume*) that the robots can
gather (ice) and can use to power the reactor. You then have the basics
for a facility that can grow over time.

I love your idea of taking the ships apart, that's how I got the idea of
throwing a nuclear reactor in there.

I'm a bit skeptic over the mass-driver idea, hell if you really want to
go that route why not use an "elastic-powered" catapult? I mean, it's
not like you are going to get wind resistance on the moon, why use
something that will use up so much juice? A well-built trebuchet
(computer controlled) will be able to launch something outside of orbit
(at the right angle, of course) given enough power. I've seen trebuchet
launch cars 200 meters away, now with a bigger unit, 1/6th the gravity
and a smaller payload, no wind resistance and a computer at the helm you
should be able to land that thing on a 1/4" hook on a orbiting ship. The
only problem is going to be the "push" that the load is going to give
you, let's face it, the orbital platform could be thrown out of orbit
with a sufficient payload. But then again, the trebuchet uses gravity so
it may not be appropriate at all - I'm just thinking out loud.

Unless the intent of the mass driver is to act like the reverse of a
vacuum cleaner and to constantly push particules out, but then you may
still have the same problem.

The reactor-powered craft that delivers goods to a space theter works
well, if they can fit those things in a sub, they can fit them into a
plane, plus you will get a lot more output that with a little kerosene
engine. If a reactor-powered subs can reach speeds of 25 knots
underwater then you should be able to go mach 2 with a reactor-powered
craft. A UAV would, of course, be the best choice.

When thinking about space, we can't always got he fancy route because we
are all thrown into an environment where the silliest thing can actually
kill you, you are not in an environment where you have ample energy not
supplies.

Now you nailed the supply part quite well, but I'm not convinced (I
didn't check any excel documents yet on the group files) that you
calculated the the mass driver's power requirements quite well.

You can't use permanently charged magnets on a particule projector, you
have to use electrically powered magnets, which suck up a lot of juice.
For a good reference (I don't have a link to give you, sorry) check out
those magnets that they use in junkyards to lift scrap, unless you are
on the electric grid, you won't be using those for very long, unless you
have a huge engine, a huge gas tank and a huge alternator.

Huge things don't ship well when it costs 500 billion just to send a
shuttle in orbit... and they take time to build. We need to put our
heads together you and I and figure out a better solution.

The Mars team found a great one when it comes to creating a robot digger
(like a worm), the initial idea was to use a laser (hello battery power,
bye bye mission) to heat the rocks and bore through, you know the
approach they went for? A hammer that winds up like a screw.

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: victoriatangoman [mailto:tango_dancer@...]
Sent: Sunday, March 14, 2004 9:51 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Jumping the Gun.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> How about sending robots to the moon? It's not like a few solar
panels
> won't come in handy and it's not as far as mars, so sending them
> commands won't take 48 hours.

Good idea.

Do you have anything to add to this post?

> If you have concrete, your can build a few basic structures (at
least,
> for the robots) Now granted that I have no idea how concrete would
> solidify in a freezing and vacuum environment, I'm just thinking
and
> inviting opinions.

Look here for a paper on lunar concrete:

http://f3.grp.yahoofs.com/v1/IA5VQPxWybEpg1xtyQHHmAQgEM_p-
J9z7obzPNwVVWrPFdYEQWySWfb-a9AEdPczn-
gK5MPqqLsriGlqxytcno6c9xAAlxcwAKp2FuuO/Concrete%20for%20Lunar%20Base%
20Construction.pdf

TangoMan

From: Karell Ste-Marie [mailto:stemarie@brain-bank.com]

> I'm a bit skeptic over the mass-driver idea, hell if you really want
to go that route why not use an "elastic-powered"
> catapult?

I'm skeptical that an elastic-powered catapult could be built which
could launch payloads to 2.4 km/sec. The nice thing about the mass
driver is that the coupling is magnetic, so we don't have to worry about
things tearing apart (or wheels flying apart, or sliding surfaces
heating, etc.).

My attitude is that back in the days when NASA had the money to spend to
assemble tiger team study groups to look at space industrialization, the
mass-driver emerged as the key to economical launch of raw material from
the moon. I'm disinclined to second-guess them. It's not even the case
that it's the first thing they looked at. They originally looked at a
rotary pellet launcher.

> I mean, it's not like you are going to get wind resistance on the
moon, why use something that will use up so
> much juice?

The requirement to launch a given kilogram from the moon at a certain
velocity involves a certain amount of kinetic energy. We will have to
pay for that energy, regardless of what method we choose. So the only
issue really is efficiency. Mass drivers, in terms of conversion of
electrical energy to kinetic, have quite high efficiencies.

Regards,

Mike Combs

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:

> First, if we are going to conquer the stars, we need to think of
> other methods of getting there and chemical propellant is not the
> trick. I would rather create a small, portable, nuclear reactor to
> power the craft from an atmospheric side of things and then use an
> ion drive in space than use chemical propellant.

I thought long and hard about different forms of propulsion and the
supply chains that each would entail.

Nuclear has much to recommend it but I was unsure of the political
feasability of launching nuclear material into orbit. Further you'd
need raction mass so the question of where that would come from
would still remain.

Ion propulsion has a pretty impressive ISp but a very low thrust so
your ship would take a long time to get anywhere even though it was
using its fuel very efficiently. Further, where would all of the
Xenon or Argon come from?

I reluctantly settled on chemical propulsion because it had high
thrust, it would use a lot of the oxygen byproduct produced from
lunar material refining and when volitiles from NEOs were refined
into hypergolic fuels oone wouldn't have to worry about cryogenic
storage issues. Further, this allows another industry to be
established, rocket fuels, and cross subsidizes the collection from
NEOs of the volitiles like carbon and nitrogen which we would be
using in industrial quantities for agriculture and inert atmosphere.

> Water? Plenty of water on the moon (I *assume*) that the robots can
> gather (ice) and can use to power the reactor. You then have the
> basics for a facility that can grow over time.

Hydrogen has been detected at the lunar poles. Whether that hydrogen
is part of frozen water or some other compounds is an open question.
I'm not sure if there is plenty of water or not.

Also, if your base is situated at the equator, where you want it to
be if you have a mass-driver firing loads to a catcher at L-2, then
you have to deal with a secondary base at the poles whose only
purpose is to mine ice. How will you get the ice to the equator?
Launching via rocket is very energy inefficient, and in the end I
concluded that when one considers the ancillary benefit of carbon
and nitrogen, it made more sense to get the hydrogen from NEOs than
from the lunar poles.

> I'm a bit skeptic over the mass-driver idea, hell if you really
> want to go that route why not use an "elastic-powered" catapult?

Mike already addressed the energy issue, and I'm on board with his
explanation. A mass driver is very efficient at converting energy
into work. It takes a lot of energy to propell the mass to lunar
escape velocity and the mass driver has no moving parts.

I've run into people who are skeptics about the mass driver concept,
but never have I run into a mass-driver skeptic who has read
O'Neill's "The High Frontier." Have you read it? He does such a good
job in detailing the physics and rationales that I think he
addresses all of the issues skeptics have.

> If a reactor-powered subs can reach speeds of 25 knots
> underwater then you should be able to go mach 2 with a reactor-
> powered craft. A UAV would, of course, be the best choice.

I'm not quite sure what you mean by this, but I don't think a
nuclear powered UAV is going to go over well with the public.

> Now you nailed the supply part quite well, but I'm not convinced (I
> didn't check any excel documents yet on the group files) that you
> calculated the the mass driver's power requirements quite well.

I'm more than happy to be double checked. I did the work in
isolation and no one has really looked at it with a critical eye.
Feel free to do so.

TangoMan

Em Seg 15 Mar 2004 15:35, victoriatangoman escreveu:
(...)
> Nuclear has much to recommend it but I was unsure of the political
> feasability of launching nuclear material into orbit. Further you'd
> need raction mass so the question of where that would come from
> would still remain.
(...)

An Orion-type ship would turn the reaction mass stuff into a non-problem.
However, it is currently politically impossible to launch a giant spaceship
propelled by H-bombs, and I would say that it will remain politically
impossible for many decades to come.

--- In spacesettlers@yahoogroups.com, Lucio de Souza Coelho
wrote:

> An Orion-type ship would turn the reaction mass stuff into a non-
problem.
> However, it is currently politically impossible to launch a giant
spaceship
> propelled by H-bombs, and I would say that it will remain
politically
> impossible for many decades to come.

Hmm, I wonder which option would be most palatable to the general
public: sending a reactor core into orbit, or launching H-bombs to
be fitted to the Orion? I'd love to witness the debate on that.

Visions of Chernobyl or visions of Bikini atoll.

TangoMan

Mike Combs wrote:

I'm skeptical that an elastic-powered catapult could be built which
could launch payloads to 2.4 km/sec. The nice thing about the mass
driver is that the coupling is magnetic, so we don't have to worry about
things tearing apart (or wheels flying apart, or sliding surfaces
heating, etc.).

Any hope that a mass driver can be used as a propulsion system in a Rocket? Is it more efficint than a chemical propulsion system?

Selvaraj.

P.S. Just read, after composing the above post:

Take along mass drivers and solar power cells. Use the unwanted material
of the asteroid in the mass drivers. You can move millions of tons, but it
will take a while.

Rick Brooks

.... interested in knowing more.

From: sraj [mailto:sraj@...]

> Any hope that a mass driver can be used as a propulsion
> system in a Rocket?

Absolutely. Back in the days of the High Frontier studies, it had been
suggested that mass-driver tugs could push payloads of cargo from LEO to
lunar orbit. Also that mass-driver tugs might go out to asteroids and
bring them (or a portion thereof) back to HEO.

Here are some pictures of mass-driver tugs:
http://members.aol.com/sandycombs/massdriv.jpg
http://members.aol.com/sandycombs/asteroid.jpg from
http://members.aol.com/oscarcombs/settle.htm

and

http://www.ssi.org/assets/images/Ch10p204.gif
http://www.ssi.org/assets/images/Ch10p218.gif
http://www.ssi.org/assets/images/Ch11p226.gif from
http://www.ssi.org/Don_Davis_Artshow.html

> Is it more efficint than a chemical
> propulsion system?

Seems like I remember O'Neill commenting that a mass-driver engine could
have twice the specific impulse of the Space Shuttle's chemical main
engines. But as Rick commented, the big advantage is that they could
use just about anything lying around for reaction mass: oxygen from an
ore-refining operation, regolith from an asteroid, etc..

Regards,

Mike Combs

Hang on here,

Why would a mass driver need fuel, doesn't it work on electricity? And
if it doesn, why not use solar power and huge capacitors? Why should we,
once again, go towards fuels that will eventually go away?

Ok, so asteroids, it's not like they are going away, but what if you
find that perfect rock, that you could essentially send as is (after
breaking it into smaller pieces), where do you get your fuel? See my
point?

Of course, it'll never happen, just like Appolo 13's incident never
could have happened and Challenger never could have happened and the
rest... It only needs to happen once to become a problem, what's the
backup plan?

We are in space, why is solar power not what is going to be used here.
Remember, I'm not a scientist, layman terms, please

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: Combs, Mike [mailto:mikecombs@...]
Sent: Tuesday, March 16, 2004 10:01 AM
To: spacesettlers@yahoogroups.com
Subject: RE: [spacesettlers] Re: Jumping the Gun.

Seems like I remember O'Neill commenting that a mass-driver engine could
have twice the specific impulse of the Space Shuttle's chemical main
engines. But as Rick commented, the big advantage is that they could
use just about anything lying around for reaction mass: oxygen from an
ore-refining operation, regolith from an asteroid, etc..

Please note that I said "reaction mass", not fuel. Solar power is
indeed the power source, the materials I mention below would be the
reaction mass.

If using regolith from the asteroid, yes, some percentage of the
asteroid will be consumed in the process. We could do some simple
resource extraction enroute, and only throw away the less-valuable
parts. This contrasts with steam rockets (be they solar or nuclear) or
any variety of hydrogen rocket, where we're throwing away the most
valuable parts.

Regards,

Mike Combs

From: Karell Ste-Marie [mailto:stemarie@brain-bank.com]
Sent: Tuesday, March 16, 2004 2:22 PM
To: spacesettlers@yahoogroups.com
Subject: RE: [spacesettlers] Re: Jumping the Gun.

Hang on here,

Why would a mass driver need fuel, doesn't it work on electricity? And
if it doesn, why not use solar power and huge capacitors? Why should we,
once again, go towards fuels that will eventually go away?

Ok, so asteroids, it's not like they are going away, but what if you
find that perfect rock, that you could essentially send as is (after
breaking it into smaller pieces), where do you get your fuel? See my
point?

Of course, it'll never happen, just like Appolo 13's incident never
could have happened and Challenger never could have happened and the
rest... It only needs to happen once to become a problem, what's the
backup plan?

We are in space, why is solar power not what is going to be used here.
Remember, I'm not a scientist, layman terms, please

Karell Ste-Marie
C.I.O. - BrainBank Inc.

Mike,

Understood, but what is reaction mass ?

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: Combs, Mike [mailto:mikecombs@...]
Sent: Tuesday, March 16, 2004 3:52 PM
To: spacesettlers@yahoogroups.com
Subject: RE: [spacesettlers] Re: Jumping the Gun.

Please note that I said "reaction mass", not fuel. Solar power is
indeed the power source, the materials I mention below would be the
reaction mass.

If using regolith from the asteroid, yes, some percentage of the
asteroid will be consumed in the process. We could do some simple
resource extraction enroute, and only throw away the less-valuable
parts. This contrasts with steam rockets (be they solar or nuclear) or
any variety of hydrogen rocket, where we're throwing away the most
valuable parts.

Regards,

Mike Combs

From: Karell Ste-Marie [mailto:stemarie@...]
Sent: Tuesday, March 16, 2004 2:22 PM
To: spacesettlers@yahoogroups.com
Subject: RE: [spacesettlers] Re: Jumping the Gun.

Hang on here,

Why would a mass driver need fuel, doesn't it work on electricity? And
if it doesn, why not use solar power and huge capacitors? Why should we,
once again, go towards fuels that will eventually go away?

Ok, so asteroids, it's not like they are going away, but what if you
find that perfect rock, that you could essentially send as is (after
breaking it into smaller pieces), where do you get your fuel? See my
point?

Of course, it'll never happen, just like Appolo 13's incident never
could have happened and Challenger never could have happened and the
rest... It only needs to happen once to become a problem, what's the
backup plan?

We are in space, why is solar power not what is going to be used here.
Remember, I'm not a scientist, layman terms, please

Karell Ste-Marie
C.I.O. - BrainBank Inc.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> Mike,
>
> Understood, but what is reaction mass ?

Strict newtonion physics. A mass driver on an asteroid will take a
tiny pebble and fire it off into space. The power to propell the
pebble will come from solar arrays. The KE of the particle = 0.5
mv^2 so the KE will grow at the square of the velocity. As the
pebble leaves the asteroid it will impart momentum against the
asteroid in the opposite directional vector.

So, the asteroid itself provides the fuel that is needed for
propulsion using the mass driver which is powered by solar cells.
Nicely self-contained.

TangoMan

Ok, so essentially the asteroid acts as the wall that prevents the
driver itself to going in the opposite direction while the pebble stays
exactly in place (in greatly exagerated terms).

Ok, I understand - however why does this cause the asteroid to loose
mass? Recoil?

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: victoriatangoman [mailto:tango_dancer@...]
Sent: Tuesday, March 16, 2004 4:55 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Jumping the Gun.

So, the asteroid itself provides the fuel that is needed for
propulsion using the mass driver which is powered by solar cells.
Nicely self-contained.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> Ok, so essentially the asteroid acts as the wall that prevents the
> driver itself to going in the opposite direction while the pebble
stays
> exactly in place (in greatly exagerated terms).
>
> Ok, I understand - however why does this cause the asteroid to
loose
> mass? Recoil?

Try this experiment. Go to an ice-rink, put on a pair of skates, go
onto the surface of the ice. Do not brace yourself in any fashion
and take an object into your hands and throw it. You'll notice that
the object moves away from you and you also slide back a little.

The reason you did this on an ice surface is because we've tried to
remove as much friction from the experiment as possible. In space,
you won't have this friction to deal with. The distance you slid
backwards was determined by the mass of the object you threw and the
velocity you imparted. This translated into your body, which had a
much higher mass, so the velocity was reduced and you slid backwards
at a slower rate than the object you threw away from you.

On an asteroid, let's say of millions of tons, each pebble would
weigh 100g to 1 kg. The velocity of launch might be on the order of
2 - 10 km/sec. When this is translated back into the more massive
asteroid, the velocity change will be slight, but because there is
no resistance against motion, the velocity will be real, measurable,
and constant. Over time, as pebbles are launched every second, the
velocity grows.

As you mine these pebbles from the asteroid and launch them into
space, the asteroid loses mass because it is where all of these
pebbles are coming from.

TangoMan

TangoMan,

Tell someone something, and he might forget
Show someone something, and he might remember
Involve someone, and he might understand

Thanks for the explanation. Now, I understand

Karell Ste-Marie
C.I.O. - BrainBank Inc.

From: victoriatangoman [mailto:tango_dancer@...]
Sent: Tuesday, March 16, 2004 7:55 PM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] Re: Jumping the Gun.

--- In spacesettlers@yahoogroups.com, "Karell Ste-Marie"
wrote:
> Ok, so essentially the asteroid acts as the wall that prevents the
> driver itself to going in the opposite direction while the pebble
stays
> exactly in place (in greatly exagerated terms).
>
> Ok, I understand - however why does this cause the asteroid to
loose
> mass? Recoil?

Try this experiment. Go to an ice-rink, put on a pair of skates, go
onto the surface of the ice. Do not brace yourself in any fashion
and take an object into your hands and throw it. You'll notice that
the object moves away from you and you also slide back a little.

The reason you did this on an ice surface is because we've tried to
remove as much friction from the experiment as possible. In space,
you won't have this friction to deal with. The distance you slid
backwards was determined by the mass of the object you threw and the
velocity you imparted. This translated into your body, which had a
much higher mass, so the velocity was reduced and you slid backwards
at a slower rate than the object you threw away from you.

On an asteroid, let's say of millions of tons, each pebble would
weigh 100g to 1 kg. The velocity of launch might be on the order of
2 - 10 km/sec. When this is translated back into the more massive
asteroid, the velocity change will be slight, but because there is
no resistance against motion, the velocity will be real, measurable,
and constant. Over time, as pebbles are launched every second, the
velocity grows.

As you mine these pebbles from the asteroid and launch them into
space, the asteroid loses mass because it is where all of these
pebbles are coming from.

TangoMan

Subject:
Re: [spacesettlers] Re: Jumping the Gun.
Date:
Tue, 16 Mar 2004 20:07:24 +0530
From:
sraj
Reply-To:
spacesettlers@yahoogroups.com
To:
spacesettlers@yahoogroups.com
References:
1

Mike Combs wrote:

I'm skeptical that an elastic-powered catapult could be built which
could launch payloads to 2.4 km/sec. The nice thing about the mass
driver is that the coupling is magnetic, so we don't have to worry
about
things tearing apart (or wheels flying apart, or sliding surfaces
heating, etc.).

Any hope that a mass driver can be used as a propulsion system in a
Rocket? Is it more efficint than a chemical propulsion system?

Selvaraj.

P.S. Just read, after composing the above post:

Take along mass drivers and solar power cells. Use the unwanted
material
of the asteroid in the mass drivers. You can move millions of tons,
but it
will take a while.

Rick Brooks

.... interested in knowing more.

Try O'Neill's High Frontier. I believe his grad students did a lot of the
calculations on mass drivers as well as built a working model.

But basically, unlike a rocket, we've got power as long as the solar cells
are in the sun. The mass driver shoots out chunks of the asteroid. By
Newton's first law, for every reaction there is an opposite and equal reaction.

So the asteroid is pushed. A rocket has much more push. But a rocket has
to carry fuel. the mass drivers work slow, but steady. In the long run,
the asteroid would be going faster than a rocket.

And a long time to slow down. For safety's shake, I'd recommend easing it
into L4 or L5, the points on lunar orbit leading or lagging the Moon by 60
degrees. These seem to be relatively stable points; Trojan asteroids are
in those positions leading and lagging Jupiter by 60 degrees.

It would be quicker to loop right by Earth and slow the asteroid down by
braking it in the upper atmosphere. But a mistake could be very, very messy.

Rick Brooks

Hi Ste-Marie,

On Earth, in a car, we move by traction (friction). In space we can move in one of two ways, by external force, or by reaction force. External force so far as we know in the Solar System, can only be applied by Solar Wind, which is very feeble - and for which you would need large solar sails. Reaction force is the standard way to move in space, where you throw away a part of the mass of the system, and by Newtonian mechanics (The third law, to every action there is an equal and opposite reaction), you move in the opposite direction. That is why a mighty rocket delivers only a fraction of its original mass as payload - the rocket sacrifices itself to impart high velocity to the payload..

It is worth reviewing what we Indians call 'Fundas' once in a while. Half the mistakes scientists make is not in high-flown equations, but in simple things, so your questions are very pertinent.

Regards
Selvaraj

Subject:
Re: [spacesettlers] Re: Jumping the Gun.
Date:
Tue, 16 Mar 2004 20:07:24 +0530
From:
sraj
Reply-To:
spacesettlers@yahoogroups.com
To:
spacesettlers@yahoogroups.com
References:
1

Mike Combs wrote:

I'm skeptical that an elastic-powered catapult could be built which
could launch payloads to 2.4 km/sec. The nice thing about the mass
driver is that the coupling is magnetic, so we don't have to worry
about
things tearing apart (or wheels flying apart, or sliding surfaces
heating, etc.).

Any hope that a mass driver can be used as a propulsion system in a
Rocket? Is it more efficint than a chemical propulsion system?

Selvaraj.

P.S. Just read, after composing the above post:

Take along mass drivers and solar power cells. Use the unwanted
material
of the asteroid in the mass drivers. You can move millions of tons,
but it
will take a while.

Rick Brooks

.... interested in knowing more.

Try O'Neill's High Frontier. I believe his grad students did a lot of the
calculations on mass drivers as well as built a working model.

But basically, unlike a rocket, we've got power as long as the solar cells
are in the sun. The mass driver shoots out chunks of the asteroid. By
Newton's first law, for every reaction there is an opposite and equal reaction.

So the asteroid is pushed. A rocket has much more push. But a rocket has
to carry fuel. the mass drivers work slow, but steady. In the long run,
the asteroid would be going faster than a rocket.

And a long time to slow down. For safety's shake, I'd recommend easing it
into L4 or L5, the points on lunar orbit leading or lagging the Moon by 60
degrees. These seem to be relatively stable points; Trojan asteroids are
in those positions leading and lagging Jupiter by 60 degrees.

It would be quicker to loop right by Earth and slow the asteroid down by
braking it in the upper atmosphere. But a mistake could be very, very messy.

Rick Brooks