The key factor in the development of space is the cost of moving
people and cargo from the Earth's surface to orbit. I propose
building a mass driver along the ridge of the Himalayas.

A mass driver consists of a series of solenoids, which move a charged
projectile along their length by alternately turning on and off one
by one.

The mass driver I propose would consist of solenoids 100 m in
diameter, made of a superconducting material. They would be spaced
along the mountain range so that they would provide a constant 3g
acceleration. The projectile would resemble a supersonic airplane,
gliding from one solenoid to the next. A maglev track could be used
to provide the initial velocity required for the airfoil to provide
sufficient lift to carry the craft from one solenoid to the next.
The craft would make a series of parabolic glides until it received
its final boost at the end of the mass driver.

I figure that such a mass driver would have to be about 1500 miles
long to achieve escape velocity at 3g.

:) ed

From: Ed Minchau [mailto:ed_minchau@...]

A mass driver consists of a series of solenoids, which move a charged
projectile

I think you mean a "magnetic" projectile. For example, the O'Neill mass
driver used a "bucket" which had superconducting coils. But the issue there
is circulating currents, not charge.

along their length by alternately turning on and off one
by one.

The mass driver I propose would consist of solenoids 100 m in
diameter,

Wow, nobody can accuse you of thinking small. I once designed a space
launcher for a sci-fi novella. (
http://members.aol.com/howiecombs/bridge.htm
) Bearing in mind that the
expense of the launcher would be directly proportional to its size, I made
it as small as possible, with a diameter just large enough to surround a
vehicle sized for passengers two abreast. But an awful lot could be
launched from such a launcher, provided that turn-around times could be made
short.

made of a superconducting material.

Actually, there's no need for the accelerating coils to be superconductive.
Each coil only fires for the briefest of instants, so dissipating the heat
is no problem. Superconducting coils in the launch vehicle would be
advantageous, though.

They would be spaced
along the mountain range so that they would provide a constant 3g
acceleration.

Again, bearing in mind that cost would scale with size, I made mine as short
as possible, and assumed a 10 G launch. This would be fine for most
reasonably-fit people for the few seconds required.

The projectile would resemble a supersonic airplane,
gliding from one solenoid to the next. A maglev track could be used
to provide the initial velocity required for the airfoil to provide
sufficient lift to carry the craft from one solenoid to the next.

In earlier mass driver models, dynamic induction levitation was used to
provide lift. Later models used a pull-only mode of operation, which
provided a strong centering force on the bucket and thus enabled them to
eliminate the levitation strips.

The craft would make a series of parabolic glides until it received
its final boost at the end of the mass driver.

I think you may be assuming a greater separation between driver coils than
what may be practical. I'll admit I don't have a firm notion of what's
correct here, but I'm thinking it would be measured in a few feet, and I
suspect you're thinking in terms of miles.

I figure that such a mass driver would have to be about 1500 miles
long to achieve escape velocity at 3g.

Mine started out at 100 km launching raw materials at 30 Gs, then was later
expanded to a little over two hundred kilometers for satellite launching at
20 Gs, then later grew to three hundred and ten kilometers (186 mi.) for 10
G launching of passengers. But like I said, this was just for a sci-fi
story. I'm not sure I really believe in 186 mile long mass drivers.

Regards,

Mike Combs

From:
Ed Minchau [mailto:ed_minchau@...]
A mass driver consists of a series of solenoids, which move a charged
projectile

I think you mean a "magnetic" projectile. For example, the O'Neill mass driver used a "bucket" which had superconducting coils. But the issue there is circulating currents, not charge.

along their length by alternately turning on and off one
by one.
The mass driver I propose would consist of solenoids 100 m in
diameter,

Wow, nobody can accuse you of thinking small. I once designed a space launcher for a sci-fi novella. (
http://members.aol.com/howiecombs/bridge.htm
) Bearing in mind that the expense of the launcher would be directly proportional to its size, I made it as small as possible, with a diameter just large enough to surround a vehicle sized for passengers two abreast. But an awful lot could be launched from such a launcher, provided that turn-around times could be made short.

made of a superconducting material.

Actually, there's no need for the accelerating coils to be superconductive. Each coil only fires for the briefest of instants, so dissipating the heat is no problem. Superconducting coils in the launch vehicle would be advantageous, though.

They would be spaced
along the mountain range so that they would provide a constant 3g
acceleration.

Again, bearing in mind that cost would scale with size, I made mine as short as possible, and assumed a 10 G launch. This would be fine for most reasonably-fit people for the few seconds required.

The projectile would resemble a supersonic airplane,
gliding from one solenoid to the next. A maglev track could be used
to provide the initial velocity required for the airfoil to provide
sufficient lift to carry the craft from one solenoid to the next.

In earlier mass driver models, dynamic induction levitation was used to provide lift. Later models used a pull-only mode of operation, which provided a strong centering force on the bucket and thus enabled them to eliminate the levitation strips.
The craft would make a series of parabolic glides until it received
its final boost at the end of the mass driver.

I think you may be assuming a greater separation between driver coils than what may be practical. I'll admit I don't have a firm notion of what's correct here, but I'm thinking it would be measured in a few feet, and I suspect you're thinking in terms of miles.
I figure that such a mass driver would have to be about 1500 miles
long to achieve escape velocity at 3g.

Mine started out at 100 km launching raw materials at 30 Gs, then was later expanded to a little over two hundred kilometers for satellite launching at 20 Gs, then later grew to three hundred and ten kilometers (186 mi.) for 10 G launching of passengers. But like I said, this was just for a sci-fi story. I'm not sure I really believe in 186 mile long mass drivers.

Regards,
Mike Combs

At 5 g the length of the mass driver is 1250 km long. The acceleration
would be constant.

Bill

--- In spacesettlers@egroups.com, "Ed Minchau"
> The key factor in the development of space is the cost of moving
> people and cargo from the Earth's surface to orbit. I propose
> building a mass driver along the ridge of the Himalayas.
>
> A mass driver consists of a series of solenoids, which move a
charged

The winds at the tops of the Himalayas can exceed 200mph, I know.
This would require control surfaces on the craft, to keep it centered
on the solenoids.

The sonic shock wave would be more of a problem for the solenoids
than in terms of sound pollution. They would need a teardrop-shaped
cross section to allow the wave to pass by them.

--- In spacesettlers@egroups.com, "Ed Minchau"
> The winds at the tops of the Himalayas can exceed 200mph, I know.
> This would require control surfaces on the craft, to keep it
centered
> on the solenoids.
>
> The sonic shock wave would be more of a problem for the solenoids
> than in terms of sound pollution. They would need a teardrop-
shaped
> cross section to allow the wave to pass by them.

Greetings Ed,

This is a great idea and if it was able to be done I'd say more
power to you but I think there are a few little problems that may
just slow down and maybe stop such a project.

First, the wind is certainly going to give you a major headache but
nothing like the one you will get from the constant rebuilding of all
your supports. The Himalayas were created when two tectonic plates
collided. The impact buckled the plates and the mountains were
raised or I should they are still being raised, the Himalayas are not
a static range of mountains, they are a growing, moving mass of rock
that is going up in places, down in others and in different
directions all over the place and it's not just the rock that is
moving, the ice moves even faster. The movement is not much mind you
but enough to cause you problems over the course of a few years for
the rock and a few days/weeks for the ice.

Next, 1500 Kms @ 3Gs will certainly get you to orbital speed, in fact
it should get you to +9 Km/sec but of course that's 1500 Kms at a
CONSTANT 3Gs. What you were describing sounds like the coils are
some distance apart and you would be getting a kick along gliding
for a bit then getting another kick long. In that case you would
need an average of 3Gs so depending on the size of the gap you would
need a kick that was +3Gs and the bigger the gap the size of the +.

Finally, what I think may just be the biggest problem for is not
really a technical one, take good look at a map and look at the
length of the mountain range and mark out 1500 Kms, look at the angle
the range is inclined at (that is the direction it points), and then
consider which nations you would need to pass through and possibly
overfly for the best launch angle. When teams were trying for the
round the world balloon record they had problems getting permission
to overfly, you want a lot more than that. Not to mention that at
lest one of the countries you would need permission from is a
possible competitor. Good luck, you will need it.

Darren Brown

--- In spacesettlers@egroups.com, "bill t" wrote:
>
> At 5 g the length of the mass driver is 1250 km long. The
acceleration
> would be constant.
>
> Bill
>
> --- In spacesettlers@egroups.com, "Ed Minchau"
> wrote:
> > The key factor in the development of space is the cost of moving
> > people and cargo from the Earth's surface to orbit. I propose
> > building a mass driver along the ridge of the Himalayas.
> >
> > A mass driver consists of a series of solenoids, which move a
> charged
> > projectile along their length by alternately turning on and off
one
> > by one.
> >
> > The mass driver I propose would consist of solenoids 100 m in
> > diameter, made of a superconducting material. They would be
spaced
> > along the mountain range so that they would provide a constant 3g
> > acceleration. The projectile would resemble a supersonic
airplane,
> > gliding from one solenoid to the next. A maglev track could be
used
> > to provide the initial velocity required for the airfoil to
provide
> > sufficient lift to carry the craft from one solenoid to the
next.
> > The craft would make a series of parabolic glides until it
received
> > its final boost at the end of the mass driver.
> >
> > I figure that such a mass driver would have to be about 1500
miles
> > long to achieve escape velocity at 3g.
> >
> > :) ed

To minimize cost, you must maximize G loading. Astronauts can
tolerate 20Gs and public passengers around 10Gs for a launch.
Cheers,
Tom Tucker

On Wed, 10 January 2001, tntucker@... wrote:

>
> --- In spacesettlers@egroups.com, "bill t" wrote:
> >
> > At 5 g the length of the mass driver is 1250 km long. The
> acceleration
> > would be constant.
> >
> > Bill
> >
> > --- In spacesettlers@egroups.com, "Ed Minchau"
> > wrote:
> > > The key factor in the development of space is the cost of moving
> > > people and cargo from the Earth's surface to orbit. I propose
> > > building a mass driver along the ridge of the Himalayas.
> > >
> > > A mass driver consists of a series of solenoids, which move a
> > charged
> > > projectile along their length by alternately turning on and off
> one
> > > by one.
> > >
> > > The mass driver I propose would consist of solenoids 100 m in
> > > diameter, made of a superconducting material. They would be
> spaced
> > > along the mountain range so that they would provide a constant 3g
> > > acceleration. The projectile would resemble a supersonic
> airplane,
> > > gliding from one solenoid to the next. A maglev track could be
> used
> > > to provide the initial velocity required for the airfoil to
> provide
> > > sufficient lift to carry the craft from one solenoid to the
> next.
> > > The craft would make a series of parabolic glides until it
> received
> > > its final boost at the end of the mass driver.
> > >
> > > I figure that such a mass driver would have to be about 1500
> miles
> > > long to achieve escape velocity at 3g.
> > >
> > > :) ed
>
> To minimize cost, you must maximize G loading. Astronauts can
> tolerate 20Gs and public passengers around 10Gs for a launch.
> Cheers,
> Tom Tucker
>
..........

The maximum acceleration a human body can take and still survive is about 200g. There has been a racecar driver who hit the wall head-on at over 200 km/h, and decellerated in about one meter; he received first aid within seconds, and prompt medical treatment. He was comatose, but eventually recovered. That was about 150 g for less than 4 tenths of a second.

Pilots (and astronauts) generally black out at 10-12 g, and maintaining blood flow to the brain requires a specialized breathing technique, something like pushing really hard when constipated. Anything above 6 g is uncomfortable.

The US Space Shuttle experiences about 2.5-3 g of acceleration, to provide protection for the sensitive life experiments they carry. As John Glen proved, this acceleration is even tolerable for senior citizens, if they are in relatively good health.

For an unmanned, strictly cargo carrying craft, I would expect a much shorter accelerator, as you could use much higher acceleration. 200g is not unfeasible.

Although the physical structure of the mass driver is only at fixed points in space, the acceleration takes place along the entire length. It is not the solenoids themselves that produce the acceleration, it is the magnetic field they produce, and that is controlled though the entire length of the mass driver, even beyond the final solenoid.

All mountain ranges are moving in several directions at once. The rings would have to be gimbal-mounted and controlled to compensate for the subtly shifting terrain.

Political considerations will always be important; I suggested the Himalayas because they are near the equator and roughly parallel to it, and because the range is long enough to support 3g acceleration. I realize that the necessary trajectory is East, through, over or near such hotspots as Nepal, Tibet, Kashmir, China, North Korea, Pakistan, etc. For Polar orbits, perhaps using the Rockies, Andes, or Urals may prove to be more politically acceptable.

There are also religious factors to consider; I can't imagine trying to tell some monk that we have to tear down his temple to make way for the mass driver.

:) ed

>

Get your own free, private space on the Web at http://www.intranets.com.

--- In spacesettlers@egroups.com, "Darren Brown" wrote:
> --- In spacesettlers@egroups.com, "Ed Minchau"
> wrote:
> > The winds at the tops of the Himalayas can exceed 200mph, I
know.
> > This would require control surfaces on the craft, to keep it
> centered
> > on the solenoids.
> >
> > The sonic shock wave would be more of a problem for the solenoids
> > than in terms of sound pollution. They would need a teardrop-
> shaped
> > cross section to allow the wave to pass by them.
>
> Greetings Ed,
>
> This is a great idea and if it was able to be done I'd say more
> power to you but I think there are a few little problems that may
> just slow down and maybe stop such a project.
>
> First, the wind is certainly going to give you a major headache but
> nothing like the one you will get from the constant rebuilding of
all
> your supports. The Himalayas were created when two tectonic plates
> collided. The impact buckled the plates and the mountains were
> raised or I should they are still being raised, the Himalayas are
not
> a static range of mountains, they are a growing, moving mass of
rock
> that is going up in places, down in others and in different
> directions all over the place and it's not just the rock that is
> moving, the ice moves even faster. The movement is not much mind
you
> but enough to cause you problems over the course of a few years for
> the rock and a few days/weeks for the ice.
>
> Next, 1500 Kms @ 3Gs will certainly get you to orbital speed, in
fact
> it should get you to +9 Km/sec but of course that's 1500 Kms at a
> CONSTANT 3Gs. What you were describing sounds like the coils are
> some distance apart and you would be getting a kick along gliding
> for a bit then getting another kick long. In that case you would
> need an average of 3Gs so depending on the size of the gap you
would
> need a kick that was +3Gs and the bigger the gap the size of the +.

1500 MILES ~ 2400 km. At 3g, that is almost 12km/s. Escape velocity
(not orbital velocity) is about 11.2 km/s; for orbital velocity you
could get by with a shorter accelerator or lower acceleration.

Acceleration does not occur only at the solenoids, it occurs between
them as well. Each solenoid provides both a pull as the craft
approaches, and a push as the craft passes through amd recedes. The
electromagnetic field along the accelerator is equivalent to a
continuous magnetic tube, with a moving set of poles; one behind the
craft pushing, and the other in front pulling. It is these poles
which are accelerating, they just bring the craft along for the ride .

>
> Finally, what I think may just be the biggest problem for is not
> really a technical one, take good look at a map and look at the
> length of the mountain range and mark out 1500 Kms, look at the
angle
> the range is inclined at (that is the direction it points), and
then

Ed Minchau wrote:

> --- In spacesettlers@egroups.com, "Darren Brown" wrote:
> > --- In spacesettlers@egroups.com, "Ed Minchau"
> > wrote:
> > > The winds at the tops of the Himalayas can exceed 200mph, I
> know.
> > > This would require control surfaces on the craft, to keep it
> > centered
> > > on the solenoids.
> > >
> > > The sonic shock wave would be more of a problem for the solenoids
> > > than in terms of sound pollution. They would need a teardrop-
> > shaped
> > > cross section to allow the wave to pass by them.
> >
> > Greetings Ed,
> >
> > This is a great idea and if it was able to be done I'd say more
> > power to you but I think there are a few little problems that may
> > just slow down and maybe stop such a project.
> >
> > First, the wind is certainly going to give you a major headache but
> > nothing like the one you will get from the constant rebuilding of
> all
> > your supports. The Himalayas were created when two tectonic plates
> > collided. The impact buckled the plates and the mountains were
> > raised or I should they are still being raised, the Himalayas are
> not
> > a static range of mountains, they are a growing, moving mass of
> rock
> > that is going up in places, down in others and in different
> > directions all over the place and it's not just the rock that is
> > moving, the ice moves even faster. The movement is not much mind
> you
> > but enough to cause you problems over the course of a few years for
> > the rock and a few days/weeks for the ice.
> >
> > Next, 1500 Kms @ 3Gs will certainly get you to orbital speed, in
> fact
> > it should get you to +9 Km/sec but of course that's 1500 Kms at a
> > CONSTANT 3Gs. What you were describing sounds like the coils are
> > some distance apart and you would be getting a kick along gliding
> > for a bit then getting another kick long. In that case you would
> > need an average of 3Gs so depending on the size of the gap you
> would
> > need a kick that was +3Gs and the bigger the gap the size of the +.
>
> 1500 MILES ~ 2400 km. At 3g, that is almost 12km/s. Escape velocity
> (not orbital velocity) is about 11.2 km/s; for orbital velocity you
> could get by with a shorter accelerator or lower acceleration.
>
> Acceleration does not occur only at the solenoids, it occurs between
> them as well. Each solenoid provides both a pull as the craft
> approaches, and a push as the craft passes through amd recedes. The
> electromagnetic field along the accelerator is equivalent to a
> continuous magnetic tube, with a moving set of poles; one behind the
> craft pushing, and the other in front pulling. It is these poles
> which are accelerating, they just bring the craft along for the ride .
>
> > Finally, what I think may just be the biggest problem for is not
> > really a technical one, take good look at a map and look at the
> > length of the mountain range and mark out 1500 Kms, look at the
> angle
> > the range is inclined at (that is the direction it points), and
> then
> > consider which nations you would need to pass through and possibly
> > overfly for the best launch angle. When teams were trying for the
> > round the world balloon record they had problems getting permission
> > to overfly, you want a lot more than that. Not to mention that at
> > lest one of the countries you would need permission from is a
> > possible competitor. Good luck, you will need it.
> >
> > Darren Brown
>

Ed,

Sorry about the mistake with the mile and kilometres, problem is like
most of educated world I tend to deal in metric and you threw me by
starting metric with the dimensions of the rings, 100 metres and then
switching to imperial units, 1500 miles, seems I remember that NASA had
a small mishap with one of their Mars probes because of this kind of
mistake.

First, I don't understand why you need to get to escape velocity, once
your in orbit you can use slower but cheaper ways to manage that. It
will also give you a shorter and therefore cheaper magnetic driver.

Next, I would really like to know just how far apart you want the rings
of your driver? Magnetic fields, like all fields, works on an inverse
square factor as I'm sure you know, if you intent to have an actual
CONSTANT 3G field rather than an AVERAGE 3G field you are going to need
to be able to vary the power of your field and if your magnetic sources
are going to effect your craft while it is a distance away, what is to
stop it from moving other things around it. Unless you have found some
way making a magnetic field form itself into a tube, without something
outside forcing it to. You say above that what you are talking about is
the equivalent to a continuous magnetic tube. I don't see how that is
possible without some kind of device outside making it into a tube.

Next, Gimbals won't cut it, sorry, what you would be dealing with is a
constant, unpredictable and complex 3 dimensional motion. The big
problem is the unpredictable part. You must expect seismic movements in
that area.

Next, politics will play a major part of any large project in that part
of the world and you will also have problems with the lack of
infrastructure.

Finally, why bother with the whole thing, it's large, expensive, and
prone to a falling out between nations. A far better option would be
something that you do from wholly within a single nation. Your location
or at lest its elevation would assist with a laser launch system,
although I am unsure of how much and if the benefit would outweigh the
costs.

Darren Brown

Ed Minchau wrote:
--- In spacesettlers@egroups.com, "Darren Brown"
> --- In spacesettlers@egroups.com, "Ed Minchau"
> wrote:
> > The winds at the tops of the Himalayas can exceed 200mph, I
know.
> > This would require control surfaces on the craft, to keep it
> centered
> > on the solenoids.
> >
> > The sonic shock wave would be more of a problem for the solenoids
> > than in terms of sound pollution. They would need a teardrop-
> shaped
> > cross section to allow the wave to pass by them.
>
> Greetings Ed,
>
> This is a great idea and if it was able to be done I'dsay more
> power to you but I think there are a few little problems thatmay
> just slow down and maybe stop such a project.
>
> First, the wind is certainly going to give you a major headachebut
> nothing like the one you will get from the constant rebuildingof
all
> your supports. The Himalayas were created when two tectonicplates
> collided. The impact buckled the plates and the mountainswere
> raised or I should they are still being raised, the Himalayasare
not
> a static range of mountains, they are a growing, moving massof
rock
> that is going up in places, down in others and in different
> directions all over the place and it's not just the rock thatis
> moving, the ice moves even faster. The movement is notmuch mind
you
> but enough to cause you problems over the course of a few yearsfor
> the rock and a few days/weeks for the ice.
>
> Next, 1500 Kms @ 3Gs will certainly get you to orbital speed,in
fact
> it should get you to +9 Km/sec but of course that's 1500 Kmsat a
> CONSTANT 3Gs. What you were describing sounds like thecoils are
> some distance apart and you would be getting a kick along gliding
> for a bit then getting another kick long. In that caseyou would
> need an average of 3Gs so depending on the size of the gap you
would
> need a kick that was +3Gs and the bigger the gap the size ofthe +.
1500 MILES ~ 2400 km. At 3g, that is almost 12km/s. Escape velocity
(not orbital velocity) is about 11.2 km/s; for orbital velocityyou
could get by with a shorter accelerator or lower acceleration.
Acceleration does not occur only at the solenoids, it occurs between
them as well. Each solenoid provides both a pull as the craft
approaches, and a push as the craft passes through amd recedes. The
electromagnetic field along the accelerator is equivalent to a
continuous magnetic tube, with a moving set of poles; one behindthe
craft pushing, and the other in front pulling. It is thesepoles
which are accelerating, they just bring the craft along for theride .
>
> Finally, what I think may just be the biggest problem for isnot
> really a technical one, take good look at a map and look at the
> length of the mountain range and mark out 1500 Kms, look at the
angle
> the range is inclined at (that is the direction it points), and
then
> consider which nations you would need to pass through and possibly
> overfly for the best launch angle. When teams were tryingfor the
> round the world balloon record they had problems getting permission
> to overfly, you want a lot more than that. Not to mentionthat at
> lest one of the countries you would need permission from is a
> possible competitor. Good luck, you will need it.
>
> Darren Brown

Ed,
Sorry about the mistake with the mile and kilometres, problem is likemost of educated world I tend to deal in metric and you threw me by startingmetric with the dimensions of the rings, 100 metres and then switchingto imperial units, 1500 miles, seems I remember that NASA had a small mishapwith one of their Mars probes because of this kind of mistake.
First, I don't understand why you need to get to escape velocity, onceyour in orbit you can use slower but cheaper ways to manage that. It will also give you a shorter and therefore cheaper magnetic driver.
Next, I would really like to know just how far apart you want the ringsof your driver? Magnetic fields, like all fields, works on an inversesquare factor as I'm sure you know, if you intent to have an actual CONSTANT3G field rather than an AVERAGE 3G field you are going to need to be ableto vary the power of your field and if your magnetic sources are goingto effect your craft while it is a distance away, what is to stop it frommoving other things around it. Unless you have found some way makinga magnetic field form itself into a tube, without something outside forcingit to. You say above that what you are talking about is the equivalentto a continuous magnetic tube. I don't see how that is possiblewithout some kind of device outside making it into a tube.
Next, Gimbals won't cut it, sorry, what you would be dealing with isa constant, unpredictable and complex 3 dimensional motion. The bigproblem is the unpredictable part. You must expect seismic movementsin that area.
Next, politics will play a major part of any large project in that partof the world and you will also have problems with the lack of infrastructure.
Finally, why bother with the whole thing, it's large, expensive, andprone to a falling out between nations. A far better option wouldbe something that you do from wholly within a single nation. Yourlocation or at lest its elevation would assist with a laser launch system,although I am unsure of how much and if the benefit would outweigh thecosts.

Darren Brown

--- In spacesettlers@egroups.com, Darren Brown wrote:

> Ed,
>
> Sorry about the mistake with the mile and kilometres, problem is
like
> most of educated world I tend to deal in metric and you threw me by
> starting metric with the dimensions of the rings, 100 metres and
then
> switching to imperial units, 1500 miles, seems I remember that NASA
had
> a small mishap with one of their Mars probes because of this kind of
> mistake.
>

Sorry, I am Canadian, and I was in elementary school when we switched
to metric. I am familiar with both systems. In future I will stick
strictly to metric units.

> First, I don't understand why you need to get to escape velocity,
once
> your in orbit you can use slower but cheaper ways to manage that.

I based my calculations on the maximum velocity that would possibly
be required. Shorter is good, LEO would require 1050 km at 3g.

It
> will also give you a shorter and therefore cheaper magnetic driver.
>
> Next, I would really like to know just how far apart you want the
rings
> of your driver? Magnetic fields, like all fields, works on an
inverse
> square factor as I'm sure you know, if you intent to have an actual
> CONSTANT 3G field rather than an AVERAGE 3G field you are going to
need

It's not like there is a barrier in the magnetic field between the
solenoids. The magnetic field lines between them connect, but the
timing must be precise. The energy of the field is concentrated
along its length, not radiated perpendicularly.

> to be able to vary the power of your field and if your magnetic
sources
> are going to effect your craft while it is a distance away, what is
to
> stop it from moving other things around it. Unless you have found
some
> way making a magnetic field form itself into a tube, without
something
> outside forcing it to.

That's the whole idea behind the mass driver.

You say above that what you are talking about is
> the "equivalent to a continuous magnetic tube". I don't
see how
that is
> possible without some kind of device outside making it into a tube.
>
> Next, Gimbals won't cut it, sorry, what you would be dealing with
is a
> constant, unpredictable and complex 3 dimensional motion. The big
> problem is the unpredictable part. You must expect seismic
movements in
> that area.

Part of the reason the rings are so big is to allow for a wide margin
of error. A craft 30m across would still have a 35m margin of error
in its trajectory.

>
> Next, politics will play a major part of any large project in that
part
> of the world and you will also have problems with the lack of
> infrastructure.
>

Yes. Perhaps a polar orbit is better, say with the launch site in
Chile or Canada

> Finally, why bother with the whole thing, it's large, expensive, and
> prone to a falling out between nations. A far better option would
be
> something that you do from wholly within a single nation. Your
location
> or at lest its elevation would assist with a laser launch system,
> although I am unsure of how much and if the benefit would outweigh
the
> costs.
>

The idea is to reduce launch costs to a few USD per kilogram. All of
the fuel is on the ground, all you launch is payload. It could be
powered off the existing grid if it were done in Canada. The
flightpath could be along one of several roughly parallel north-south
ridges, each of which is over 1050 km long; I can see one of them
from my house. With operating costs low due to the superconducting
wires in the solenoids, several launches a day are possible.

All of the infrastructure would be on the ground, pollution (except
noise pollution from the sonic boom) is low, operating costs are low,
all of which lead to cheap access. The launcher would be a virtual
monopoly on all space launches, and would change utilization of LEO
the way PCs changed computing.

:) ed

--- In spacesettlers@egroups.com, "Ed Minchau"
> The key factor in the development of space is the cost of moving
> people and cargo from the Earth's surface to orbit. I propose
> building a mass driver along the ridge of the Himalayas.
>
> A mass driver consists of a series of solenoids, which move a
charged
> projectile along their length by alternately turning on and off one
> by one.
>
> The mass driver I propose would consist of solenoids 100 m in
> diameter, made of a superconducting material. They would be spaced
> along the mountain range so that they would provide a constant 3g
> acceleration. The projectile would resemble a supersonic airplane,
> gliding from one solenoid to the next. A maglev track could be
used
> to provide the initial velocity required for the airfoil to provide
> sufficient lift to carry the craft from one solenoid to the next.
> The craft would make a series of parabolic glides until it received
> its final boost at the end of the mass driver.
>
> I figure that such a mass driver would have to be about 1500 miles
> long to achieve escape velocity at 3g.
>
> :) ed

But why not design for 10 or 20 Gs?
Tom Tucker

--- In spacesettlers@egroups.com, tntucker@c... wrote:
> --- In spacesettlers@egroups.com, "Ed Minchau"
> wrote:

> > I figure that such a mass driver would have to be about 1500
miles
> > long to achieve escape velocity at 3g.
> >
> > :) ed
>
> But why not design for 10 or 20 Gs?
> Tom Tucker

For human beings, stick with 3g. There are 3 or 4 mountain ranges in
British Columbia and the Yukon, Canada, that could support a railgun
that carries human cargo.

For non-living cargo, I would definitely use higher accelerations.
At 20g, the mass driver would need to be about 160 km long to achieve
low earth orbit. There must be dozens of sites around the world that
meet the folowing criteria:

- over 160 km long
- high above sea level
- nearby power, road, train, and telecommunication infrastructure

The solenoids would have to be placed much closer together, and they
could be smaller.

wow, this might actually be much less expensive than I thought...

:) ed

Ed, Tom & others,

This idea of some kind of very large magnetic launch system seems to
really be popular, I wonder why, sometimes it seems that is the fact
that it's big, what's the benefit of your launch system being 100 or
1,000 or 10,000 Kms long? My problem with such large systems is that
while they make great settings for a story, they have practical,
logistical problems that are very hard to solve, an example is
problem of just acquiring the land to build the thing, you will need
both public and private land. It is very simple to say that the
government of the day could just compulsorily acquire it but given
the number of people involved to would be giving the opposition
political fuel for years. Then there is the environmental problems
and while people may think they would be small or non-existent, just
showing that is a major headache, then there is the cost and
maintenance. Big projects such as a magnetic launch system may one
day happen but I think I will be betting on other methods killing it,
with the possible exception of the maglev system NASA is looking at
but that is just a way to start and get moving, then other things
take over, being just a few kilometres long it doesn't run into the
big problems.

A few articles by Tim Beardsley, staff writer for Scientific
American The first one has a bit on Light Craft in it and is worth
reading, it's under the sub heading "Beam me up".

Light Craft & others.
http://www.sciam.com/1999/0299issue/0299beardsley.html

Making Money in Space
http://www.sciam.com/1999/0399space/0399alpert.html

Trends in Space
http://www.sciam.com/0696issue/0696trends.html

The Future in space
http://www.sciam.com/1999/0399space/0399quicksummary.html

Summary of articles
http://www.sciam.com/1999/0299issue/0299quicksummary.html

Just a couple of things to think about. The elegance or beauty or a
system or even just how much you would love to ride on one is never
going to make it happen but there are people currently working on
ways to make it easier to get to orbit and once there you are half
way home.

Darren Brown

--- In spacesettlers@egroups.com, "Darren Brown" wrote:
> Ed, Tom & others,
>
> This idea of some kind of very large magnetic launch system seems
to
> really be popular, I wonder why, sometimes it seems that is the
fact
> that it's big, what's the benefit of your launch system being 100
or
> 1,000 or 10,000 Kms long?

The length of the accelerator (d), the (average) acceleration (a),
and the muzzle velocity (v sub f) are related by the following
equation:

2
V = 2 * a * d
f

The maximum allowable acceleration and the maximum desired orbit
limit the minimum length of the accelerator. If acceleration of
human cargo to escape velocity is desired, the maximum allowable
acceleration would be 3g's, and the minimum length of 2400 kilometers.

If you want to launch straight cargo at 20g acceleration into low
earth orbit, you only need 150 km of accelerator.

The Physics are the same whether you use a stage rocket like the
Saturn V, or a composite structure like the Space Shuttle, or an
electromagnetic gun. The Energy requirements are the same.

With conventional launch systems, you have several drawbacks:
- explosive rocket fuel that must be processed, stored, pumped, etc
in specially made facilities, and eventually ignited
- takeoff in most cases at sea level, through the thickest layers of
the atmosphere
- excess weight that must be lifted to near-orbital speeds before
being discarded (like the shuttle external fuel tank), or re-used
like the shuttle solid boosters. Large numbers of people and ships
are required to salvage the boosters.

With a mass driver, the fuel is electricity, taken off the same power
grid as your computer. It all stays on the ground. So does your
propulsion system, which can be maintained directly from ground
bases. All you launch is payload. Launch systems can be automated,
enabling multiple daily launches. It is all based on existing
technology.

> My problem with such large systems is that
> while they make great settings for a story, they have practical,
> logistical problems that are very hard to solve, an example is
> problem of just acquiring the land to build the thing, you will
need
> both public and private land.

What did Kennedy say in his we will go to the moon speech? "We go
there not because it is easy, but because it is hard." ... or
something like that. The practical, logistical problems that need to
be covered are:
- physics and engineering design: if these aren't done right, nothing
else happens.
- sound business decisions: the US space program is divided up among
several states; launch facilities in Florida, Mission Control in
Texas, and landing facilities in California, for instance. The
reasons for this are largely political. Both Florida and Texas were
up for the launch site. When Texas didn't get it, the complained and
got Mission Control. Only California makes any sense, as the landing
strip is perfect.
-public acceptace of the new mode of travel: sure to come quickly
when a trip into space is as cheap as a trip across the continent.

> It is very simple to say that the
> government of the day could just compulsorily acquire it but given
> the number of people involved to would be giving the opposition
> political fuel for years. Then there is the environmental problems
> and while people may think they would be small or non-existent,
just
> showing that is a major headache, then there is the cost and
> maintenance.

It is not easy to maintain a conventional launch system, either. It
costs a lot of money to keep the Shuttle fleet going. External tanks
aren't cheap either, yet they get wasted every flight.

> Big projects such as a magnetic launch system may one
> day happen but I think I will be betting on other methods killing
it,
> with the possible exception of the maglev system NASA is looking at
> but that is just a way to start and get moving, then other things
> take over, being just a few kilometres long it doesn't run into the
> big problems.
>

The "other things that take over" you mention are what I am talking
about. Start with a maglev track to overcome static friction and
build up some speed, then the solenoids take over, pulling the
payload in and pushing it out the other side to the next solenoid;
the solenoid's EM influence extends for some distance on either side,
and if they are placed closely together the effect is an
electromagnetic tube. At supersonic speeds, the combination of
aerodynamic lift and momentum keep the craft flying between widely-
spaced rings. The payload recieves a final electromagnetic push at
the end of the railgun; perhaps a small rocket engine could boost the
craft to a higher speed, thus shortening the railgun somewhat.

> A few articles by Tim Beardsley, staff writer for Scientific
> American The first one has a bit on Light Craft in it and is worth
> reading, it's under the sub heading "Beam me up".
>
> Light Craft & others.
> http://www.sciam.com/1999/0299issue/0299beardsley.html
>
> Making Money in Space
> http://www.sciam.com/1999/0399space/0399alpert.html
>
> Trends in Space
> http://www.sciam.com/0696issue/0696trends.html
>
> The Future in space
> http://www.sciam.com/1999/0399space/0399quicksummary.html
>
> Summary of articles
> http://www.sciam.com/1999/0299issue/0299quicksummary.html
>
> Just a couple of things to think about. The elegance or beauty or
a
> system or even just how much you would love to ride on one is never
> going to make it happen but there are people currently working on
> ways to make it easier to get to orbit and once there you are half
> way home.
>

I have read all the articles you mention, and I have studied
extensively on the subject; I started my university education in
astrophysics.

At least we are agreed on the need for easier ways to get to orbit.
I have yet to do a full analysis of the costs of such a project, but
I estimate that it would be somewhere in the range of the Space
Shuttle program; ie NASA's total annual budget for three years.

:) ed

Ed,

>
> The length of the accelerator (d), the (average) acceleration (a),
> and the muzzle velocity (v sub f) are related by the following
> equation:
>
> 2
> V = 2 * a * d
> f
>

Yes, I'm familiar with the equations.

>
> The maximum allowable acceleration and the maximum desired orbit
> limit the minimum length of the accelerator. If acceleration of
> human cargo to escape velocity is desired, the maximum allowable
> acceleration would be 3g's, and the minimum length of 2400 kilometers.
>
> If you want to launch straight cargo at 20g acceleration into low
> earth orbit, you only need 150 km of accelerator.
>

I'm also aware of the effects of changing the the G loading.

>
> The Physics are the same whether you use a stage rocket like the
> Saturn V, or a composite structure like the Space Shuttle, or an
> electromagnetic gun. The Energy requirements are the same.
>

No, here you are wrong. The energy needed is related to how you use it
and what your efficiency is. The energy needed to bring a one kilo
mass from 0 to whatever speed you want and the power needed to raise the
same mass 300 Kms against gravity is not the same as what you use to put
the same mass into orbit. That will change depending on just how you do
it, none of the machines I've ever seen are 100% efficient, not all
systems are equal, except in a physics classroom.

>
> With conventional launch systems, you have several drawbacks:
> - explosive rocket fuel that must be processed, stored, pumped, etc
> in specially made facilities, and eventually ignited
> - takeoff in most cases at sea level, through the thickest layers of
> the atmosphere
> - excess weight that must be lifted to near-orbital speeds before
> being discarded (like the shuttle external fuel tank), or re-used
> like the shuttle solid boosters. Large numbers of people and ships
> are required to salvage the boosters.
>

True and I think we need something better but not necessarily bigger.

>
> With a mass driver, the fuel is electricity, taken off the same power
> grid as your computer. It all stays on the ground. So does your
> propulsion system, which can be maintained directly from ground
> bases. All you launch is payload. Launch systems can be automated,
> enabling multiple daily launches. It is all based on existing
> technology.
>

With a lightcraft the fuel, motor and all the heavy parts stay on the
ground as well.

>
> > My problem with such large systems is that
> > while they make great settings for a story, they have practical,
> > logistical problems that are very hard to solve, an example is
> > problem of just acquiring the land to build the thing, you will
> need
> > both public and private land.
>
> What did Kennedy say in his we will go to the moon speech? "We go
> there not because it is easy, but because it is hard." ... or
> something like that. The practical, logistical problems that need to
> be covered are:

Why do it the hard way if you don't have to? Hard for its own sake is
not a virtue.

>
> - physics and engineering design: if these aren't done right, nothing
> else happens.
> - sound business decisions: the US space program is divided up among
> several states; launch facilities in Florida, Mission Control in
> Texas, and landing facilities in California, for instance. The
> reasons for this are largely political. Both Florida and Texas were
> up for the launch site. When Texas didn't get it, the complained and
> got Mission Control. Only California makes any sense, as the landing
> strip is perfect.
> -public acceptace of the new mode of travel: sure to come quickly
> when a trip into space is as cheap as a trip across the continent.
>

You have left out the need to get the land to build the thing and then
there is the problem of environmental impact and other political
concerns.

>
> > It is very simple to say that the
> > government of the day could just compulsorily acquire it but given
> > the number of people involved to would be giving the opposition
> > political fuel for years. Then there is the environmental problems
> > and while people may think they would be small or non-existent,
> just
> > showing that is a major headache, then there is the cost and
> > maintenance.
>
> It is not easy to maintain a conventional launch system, either. It
> costs a lot of money to keep the Shuttle fleet going. External tanks
> aren't cheap either, yet they get wasted every flight.
>

Not easy but the government didn't need to take that much of the country
to do it.

>
> > Big projects such as a magnetic launch system may one
> > day happen but I think I will be betting on other methods killing
> it,
> > with the possible exception of the maglev system NASA is looking at
> > but that is just a way to start and get moving, then other things
> > take over, being just a few kilometres long it doesn't run into the
> > big problems.
> >
> The "other things that take over" you mention are what I am talking
> about. Start with a maglev track to overcome static friction and
> build up some speed, then the solenoids take over, pulling the
> payload in and pushing it out the other side to the next solenoid;
> the solenoid's EM influence extends for some distance on either side,
> and if they are placed closely together the effect is an
> electromagnetic tube. At supersonic speeds, the combination of
> aerodynamic lift and momentum keep the craft flying between widely-
> spaced rings. The payload recieves a final electromagnetic push at
> the end of the railgun; perhaps a small rocket engine could boost the
> craft to a higher speed, thus shortening the railgun somewhat.
>

Just how far apart are these rings of yours?

>
> > A few articles by Tim Beardsley, staff writer for Scientific
> > American The first one has a bit on Light Craft in it and is worth
> > reading, it's under the sub heading "Beam me up".
> >
> > Light Craft & others.
> > http://www.sciam.com/1999/0299issue/0299beardsley.html
> >
> > Making Money in Space
> > http://www.sciam.com/1999/0399space/0399alpert.html
> >
> > Trends in Space
> > http://www.sciam.com/0696issue/0696trends.html
> >
> > The Future in space
> > http://www.sciam.com/1999/0399space/0399quicksummary.html
> >
> > Summary of articles
> > http://www.sciam.com/1999/0299issue/0299quicksummary.html
> >
> > Just a couple of things to think about. The elegance or beauty or
> a
> > system or even just how much you would love to ride on one is never
> > going to make it happen but there are people currently working on
> > ways to make it easier to get to orbit and once there you are half
> > way home.
> >
> I have read all the articles you mention, and I have studied
> extensively on the subject; I started my university education in
> astrophysics.
>
> At least we are agreed on the need for easier ways to get to orbit.
> I have yet to do a full analysis of the costs of such a project, but
> I estimate that it would be somewhere in the range of the Space
> Shuttle program; ie NASA's total annual budget for three years.
>
> :) ed
>

I have no idea of the cost, just the thought that they may be easier to
build, even if the magnetic launch was better, that doesn't mean it will
be the way it happens, not the perfect way but that's life.

Darren Brown

Ed,

The length of the accelerator (d), the (average) acceleration (a),
and the muzzle velocity (v sub f) are related by the following
equation:
2
V = 2 * a * d
f

Yes, I'm familiar with the equations.

The maximum allowable acceleration and the maximum desired orbit
limit the minimum length of the accelerator. If accelerationof
human cargo to escape velocity is desired, the maximum allowable
acceleration would be 3g's, and the minimum length of 2400 kilometers.
If you want to launch straight cargo at 20g acceleration into low
earth orbit, you only need 150 km of accelerator.

I'm also aware of the effects of changing the the G loading.

The Physics are the same whether you use a stage rocket like the
Saturn V, or a composite structure like the Space Shuttle, or an
electromagnetic gun. The Energy requirements are the same.

No, here you are wrong. The energy needed is related to howyou use it and what your efficiency is. The energy needed tobring a one kilo mass from 0 to whatever speed you want and the power neededto raise the same mass 300 Kms against gravity is not the same as whatyou use to put the same mass into orbit. That will change dependingon just how you do it, none of the machines I've ever seen are 100% efficient,not all systems are equal, except in a physics classroom.

With conventional launch systems, you have several drawbacks:
- explosive rocket fuel that must be processed, stored, pumped,etc
in specially made facilities, and eventually ignited
- takeoff in most cases at sea level, through the thickest layersof
the atmosphere
- excess weight that must be lifted to near-orbital speeds before
being discarded (like the shuttle external fuel tank), or re-used
like the shuttle solid boosters. Large numbers of peopleand ships
are required to salvage the boosters.

True and I think we need something better but not necessarily bigger.

With a mass driver, the fuel is electricity, taken off the samepower
grid as your computer. It all stays on the ground. So does your
propulsion system, which can be maintained directly from ground
bases. All you launch is payload. Launch systems canbe automated,
enabling multiple daily launches. It is all based on existing
technology.

With a lightcraft the fuel, motor and all the heavy parts stay on the groundas well.

> My problem with such large systems is that
> while they make great settings for a story, they have practical,
> logistical problems that are very hard to solve, an example is
> problem of just acquiring the land to build the thing, you will
need
> both public and private land.
What did Kennedy say in his we will go to the moon speech? "We go
there not because it is easy, but because it is hard." ... or
something like that. The practical, logistical problems thatneed to
be covered are:
Why do it the hard way if you don't have to? Hard for itsown sake is not a virtue.

- physics and engineering design: if these aren't done right, nothing
else happens.
- sound business decisions: the US space program is divided upamong
several states; launch facilities in Florida, Mission Control in
Texas, and landing facilities in California, for instance. The
reasons for this are largely political. Both Florida andTexas were
up for the launch site. When Texas didn't get it, the complainedand
got Mission Control. Only California makes any sense, asthe landing
strip is perfect.
-public acceptace of the new mode of travel: sure to come quickly
when a trip into space is as cheap as a trip across the continent.

You have left out the need to get the land to build the thing and thenthere is the problem of environmental impact and other political concerns.

> It is very simple to say that the
> government of the day could just compulsorily acquire it butgiven
> the number of people involved to would be giving the opposition
> political fuel for years. Then there is the environmentalproblems
> and while people may think they would be small or non-existent,
just
> showing that is a major headache, then there is the cost and
> maintenance.
It is not easy to maintain a conventional launch system, either. It
costs a lot of money to keep the Shuttle fleet going. Externaltanks
aren't cheap either, yet they get wasted every flight.

Not easy but the government didn't need to take that much of the countryto do it.

> Big projects such as a magnetic launch system may one
> day happen but I think I will be betting on other methods killing
it,
> with the possible exception of the maglev system NASA is lookingat
> but that is just a way to start and get moving, then other things
> take over, being just a few kilometres long it doesn't run intothe
> big problems.
>
The "other things that take over" you mention are what I am talking
about. Start with a maglev track to overcome static frictionand
build up some speed, then the solenoids take over, pulling the
payload in and pushing it out the other side to the next solenoid;
the solenoid's EM influence extends for some distance on eitherside,
and if they are placed closely together the effect is an
electromagnetic tube. At supersonic speeds, the combinationof
aerodynamic lift and momentum keep the craft flying between widely-
spaced rings. The payload recieves a final electromagneticpush at
the end of the railgun; perhaps a small rocket engine could boostthe
craft to a higher speed, thus shortening the railgun somewhat.

Just how far apart are these rings of yours?

> A few articles by Tim Beardsley, staff writer for Scientific
> American The first one has a bit on Light Craft in it andis worth
> reading, it's under the sub heading "Beam me up".
>
> Light Craft & others.
>
http://www.sciam.com/1999/0299issue/0299beardsley.html
>
> Making Money in Space
>
http://www.sciam.com/1999/0399space/0399alpert.html
>
> Trends in Space
>
http://www.sciam.com/0696issue/0696trends.html
>
> The Future in space
>
http://www.sciam.com/1999/0399space/0399quicksummary.html
>
> Summary of articles
>
http://www.sciam.com/1999/0299issue/0299quicksummary.html
>
> Just a couple of things to think about. The elegance orbeauty or
a
> system or even just how much you would love to ride on one isnever
> going to make it happen but there are people currently workingon
> ways to make it easier to get to orbit and once there you arehalf
> way home.
>
I have read all the articles you mention, and I have studied
extensively on the subject; I started my university education in
astrophysics.
At least we are agreed on the need for easier ways to get to orbit.
I have yet to do a full analysis of the costs of such a project,but
I estimate that it would be somewhere in the range of the Space
Shuttle program; ie NASA's total annual budget for three years.
:) ed

I have no idea of the cost, just the thought that they may be easier tobuild, even if the magnetic launch was better, that doesn't mean it willbe the way it happens, not the perfect way but that's life.

Darren Brown

--- In spacesettlers@egroups.com, Darren Brown wrote:
>
> Ed,
>
> > Yes, I'm familiar with the equations.
> > I'm also aware of the effects of changing the the G loading.
>

Sorry, my caffeine system had too much blood in it, and I was cranky.

>
> > The Physics are the same whether you use a stage rocket like the
> > Saturn V, or a composite structure like the Space Shuttle, or an
> > electromagnetic gun. The Energy requirements are the same.
> >
> No, here you are wrong. The energy needed is related to how you
use it
> and what your efficiency is. The energy needed to bring a one kilo
> mass from 0 to whatever speed you want and the power needed to
raise the
> same mass 300 Kms against gravity is not the same as what you use
to put
> the same mass into orbit. That will change depending on just how
you do
> it, none of the machines I've ever seen are 100% efficient, not all
> systems are equal, except in a physics classroom.
>

The current launch trajectory of the space shuttle is highly
inefficient. Instead for direct orbital insertion, they go to about
98% of the speed required, drop down, release the fuel tank so that
it falls into the Indian Ocean, and then pick up speed again. If
they carried the fuel tank into orbit with them, it would take LESS
fuel!

By the way, NASA will launch the external tank for free, if you can
retreive it, make sure the rapid decay of the insulation coating
doesn't rain anywhere near existing sattelites or the shuttle itself,
and move it into a stable orbit. That's 30 tonnes of space-rated
Aluminum alloy, shaped as two tanks both space-rated at over 1
atmosphere of pressure, with hatches at each end, and an intertank
structure containing a beam strong enough to carry the entire
load of the solid rocket boosters, and a strongback capable of
sustaining the entire load of both boosters and the main engines. If
they go for direct orbital insertion, the tanks would contain about
1000 kg of leftover Hydrogen and 10000 kg of leftover Oxygen - very
valuable property for free, if you can get it. How's that for cheap
orbital insertion?

Even if they go for direct orbital insertion, the space shuttle must
climb directly through the thickest layer of atmosphere, since they
start at sea level. The first 3000 feet is the thickest.

> >
> > With a mass driver, the fuel is electricity, taken off the same
power
> > grid as your computer. It all stays on the ground. So does your
> > propulsion system, which can be maintained directly from ground
> > bases. All you launch is payload. Launch systems can be
automated,
> > enabling multiple daily launches. It is all based on existing
> > technology.
> >
> With a lightcraft the fuel, motor and all the heavy parts stay on
the
> ground as well.
>

Agreed, and the lightcraft is an idea well worth considering. It
does have the advantage over a railgun of a small footprint.

>
> > > My problem with such large systems is that
> > > while they make great settings for a story, they have practical,
> > > logistical problems that are very hard to solve, an example is
> > > problem of just acquiring the land to build the thing, you will
> > need
> > > both public and private land.
> >
> > What did Kennedy say in his we will go to the moon speech? "We go
> > there not because it is easy, but because it is hard." ... or
> > something like that. The practical, logistical problems that
need to
> > be covered are:
>
> Why do it the hard way if you don't have to? Hard for its own sake
is
> not a virtue.
>

I'm not necessarily saying pick the hardest way possible, far from
it. The hardest way possible is the way we are using right now, with
chemical and liquid rockets.

However, just because there are technical problems, doesn't
necessarily mean that they are insurmountable.

> >
> > - physics and engineering design: if these aren't done right,
nothing
> > else happens.
> > - sound business decisions: the US space program is divided up
among
> > several states; launch facilities in Florida, Mission Control in
> > Texas, and landing facilities in California, for instance. The
> > reasons for this are largely political. Both Florida and Texas
were
> > up for the launch site. When Texas didn't get it, the complained
and
> > got Mission Control. Only California makes any sense, as the
landing
> > strip is perfect.
> > -public acceptace of the new mode of travel: sure to come quickly
> > when a trip into space is as cheap as a trip across the continent.
> >
> You have left out the need to get the land to build the thing and
then
> there is the problem of environmental impact and other political
> concerns.
>

You're right, I did. OK, environmental impact first. This can be
divided up into several categories:
- environmental destruction due to building the project. Most of the
sites that would be suitable for building a railgun (or a lightcraft,
for that matter) would have areas where it would not be convenient to
build a road. A mountain peak that had a fairly level summit might
have sheer cliffs all around. Much of the construction equipment and
parts might need to be transported by heavy-lift helicopter. There
are some fragile ecosystems to consider, and certain mountaintops are
sacred to native peoples. But there are many, many routes to
consider if we are looking at routes of less than 200km. How many
marshlands were paved over to build Kennedy Space Center? How many
fragile desert ecosystems have gone extinct due to Edwards Air Force
Base? Has it made a difference? Has anyone noticed?
- atmospheric pollution due to system operation: clearly, the
conventional rockets are the big losers here. With
electromagnetic launch, it is as clean as the system which generated
it (coal, nuclear, hydroelectric, solar, etc).
- noise pollution: again, conventional rockets are the big loser
here. There is a sonic shock wave in either case: along the railgun
the shock wave is broken by the shape of the solenoid rings. There
is no such baffle for rockets. They also produce a noise from their
controlled explosions that literally shakes the earth.

Now, political considerations. If the railgun needs to be less than
160 km long to be effective, there are a huge number of sites around
the world that are potential candidates. Turkey is such a
mountainous country, there are several places within it that could be
used as launcher sites, in several different directions. Australia
possesses a large meteor crater in the middle of the Northern
Territory, and the south rim (near Alice Springs) looks attractive;
most of its launch trajectory would be in a roughly polar orbit, over
the Pacific. Australia also has a nice, long mountain range in
northeast Queensland and another along the coast of New South Wales.
Columbia may own day become known for more than coffee and cocaine;
the mountains on its west coast offer particularly attractive
trajectories. There are tons of sites available, with trajectories
that do not cross over other political jurisdictions.
Probably the biggest political consideration is: what if there is an
accident? What if it fails? The US space program was not prepared
for Challenger; the political fallout cost NASA years of lost time.
If a lightcraft were to suffer a catastrophic loss of power, the
craft would plummet (not designed to glide). If a railgun were to
suffer loss of power to one of its rings, it would probably still
function; if there were a catastrophic loss of power, it would depend
on the position of the projectile within the gun. Near the beginning
(while still on the maglev track) would probably not lead to
catastrophe. The first few kilometers of the railgun assembly would
probably be the most dangerous, where the rings are placed close
together; catastrophic loss of power would likely mean a crash, and
the partial or complete destruction of several rings. Near the end
of the railgun, momentum and lift would likely be enough to keep the
projectile going to an emergency landing strip. The worst-case
scenario is not as bad as the Challenger disaster: it is easier to
mass-produce solenoid rings than it is to build a new space shuttle.

>
> > > It is very simple to say that the
> > > government of the day could just compulsorily acquire it but
given
> > > the number of people involved to would be giving the opposition
> > > political fuel for years. Then there is the environmental
problems
> > > and while people may think they would be small or non-existent,
> > just
> > > showing that is a major headache, then there is the cost and
> > > maintenance.
> >
> > It is not easy to maintain a conventional launch system, either.
It
> > costs a lot of money to keep the Shuttle fleet going. External
tanks
> > aren't cheap either, yet they get wasted every flight.
> >
> Not easy but the government didn't need to take that much of the
country
> to do it.
>

In terms of total area, the US space program takes up a larger
footprint than my proposal. A strip 1km wide by 160 km long is
equivalent to a 10km/16km military base; the Kennedy Space center is
comparable in area.

>
> > > Big projects such as a magnetic launch system may one
> > > day happen but I think I will be betting on other methods
killing
> > it,
> > > with the possible exception of the maglev system NASA is
looking at
> > > but that is just a way to start and get moving, then other
things
> > > take over, being just a few kilometres long it doesn't run into
the
> > > big problems.
> > >
> > The "other things that take over" you mention are what I am
talking
> > about. Start with a maglev track to overcome static friction and
> > build up some speed, then the solenoids take over, pulling the
> > payload in and pushing it out the other side to the next solenoid;
> > the solenoid's EM influence extends for some distance on either
side,
> > and if they are placed closely together the effect is an
> > electromagnetic tube. At supersonic speeds, the combination of
> > aerodynamic lift and momentum keep the craft flying between
widely-
> > spaced rings. The payload recieves a final electromagnetic push
at
> > the end of the railgun; perhaps a small rocket engine could boost
the
> > craft to a higher speed, thus shortening the railgun somewhat.
> >
> Just how far apart are these rings of yours?
>

One of these days I am going to have to figure out all the math and
determine the optimum spacing for the rings, their size, etc. Or
perhaps someone else out there has already done the math...

>
> > > A few articles by Tim Beardsley, staff writer for Scientific
> > > American The first one has a bit on Light Craft in it and is
worth
> > > reading, it's under the sub heading "Beam me up".
> > >
> > > Light Craft & others.
> > > http://www.sciam.com/1999/0299issue/0299beardsley.html
> > >
> > > Making Money in Space
> > > http://www.sciam.com/1999/0399space/0399alpert.html
> > >
> > > Trends in Space
> > > http://www.sciam.com/0696issue/0696trends.html
> > >
> > > The Future in space
> > > http://www.sciam.com/1999/0399space/0399quicksummary.html
> > >
> > > Summary of articles
> > > http://www.sciam.com/1999/0299issue/0299quicksummary.html
> > >
> > > Just a couple of things to think about. The elegance or beauty
or
> > a
> > > system or even just how much you would love to ride on one is
never
> > > going to make it happen but there are people currently working
on
> > > ways to make it easier to get to orbit and once there you are
half
> > > way home.
> > >
> > I have read all the articles you mention, and I have studied
> > extensively on the subject; I started my university education in
> > astrophysics.
> >
> > At least we are agreed on the need for easier ways to get to
orbit.
> > I have yet to do a full analysis of the costs of such a project,
but
> > I estimate that it would be somewhere in the range of the Space
> > Shuttle program; ie NASA's total annual budget for three years.
> >
> > :) ed
> >
> I have no idea of the cost, just the thought that they may be
easier to
> build, even if the magnetic launch was better, that doesn't mean it
will
> be the way it happens, not the perfect way but that's life.
>
> Darren Brown

You're right. No government will build it unless it is politically
expedient. No private citizen or corporation would build it unless
it would turn a profit - which it would. Wish I had Bill Gates'
money!

:) ed

Greetings Al,

True, I didn't mention it directly but I'm very conscious of the
problems that can come from people who are driven by ideology rather
than rational thought. I live in Australia but even here I have
notice the activities of the ELF over the past few years as well as
others in various countries. Even here we have our own groups who
for God or Gaia or some warped political cause would think nothing of
destroying a space launch system and for some it would be even better
if there were people in it at the time. Call me a cynic but a
hypothetical; suppose I found some new way to get to orbit very
cheaply and could also build a large orbital habitats at little
cost. I decide to offer them people from all over the world, if a
group wanted one I would build them a 10,000 person habitat for some
token sum. People being what they are you can be certain that while
some, such as myself, would prefer or not mind living in a habitat
that had a culturally mixed population, not all would (Australia is a
very multicultural country and I think richer for it but I will grant
that not everyone here thinks that way), so I think it is certain
that in some cases you would have a single group, be it ethnic or
religious or maybe even political, inhabiting a single habitat. If I
was then putting the habitats into clustered orbits near to Earth, to
ease traffic back and forth. How long you think it would be before
they started to carry on the same disputes they left behind? I'm
sure some will say I shouldn't build a habitat for such a group but
what would stop them from building one for themselves? When we get
the technology to build such things you can be sure that some groups
who are fed up with the immoral, heretical, inferior, barbaric or
whatever, people around them and will want to set-up their own
version of paradise and you can be certain that somebody else will
object to something about it, not to mention the possibility of trade
or political conflicts. I'd love to think I'm wrong but down here or
up there, people are still people.

I know that the odds of a very large impact event are very low but
the consequences are huge and frankly we don't need the universe to
try to wipe us out, we're more than capable of doing it ourselves. I
have a lot of faith in the ability of people to solve their problems
but the possibility of failure is still there and I would sleep
easier if we didn't have all our eggs in one basket and besides, I'd
really love to see some of the sights the universe has to offer and a
space based society gives me the opportunities as well as the
possibilities of some jobs and recreation that are out of this world,
(sorry, I just had to ;-)but I feel that when (not if) we leave the
Earth it would be great if we could leave some of our less attractive
habits as well but somehow I think we will still be stuck with people
like the ELF, just think of what they could do on a habitat. Not a
pretty thought.

Darren Brown
Canberra Australia

Salutations Ed,

>Sorry, my caffeine system had too much blood in it, and I was cranky.

Completely understandable but I didn't mean to imply anything except
I understood the reason why you needed it to be so long and how
increasing the G loading made it shorter, this is a problem with e-
mail, a major lack of feedback (emoticon aside ;-).

>> > The Physics are the same whether you use a stage rocket like the
>> > Saturn V, or a composite structure like the Space Shuttle, or an
>> > electromagnetic gun. The Energy requirements are the same.
>>
>> No, here you are wrong. The energy needed is related to how you
>> use it and what your efficiency is. The energy needed to bring a
>> one kilo mass from 0 to whatever speed you want and the power
>> needed to raise the
>> same mass 300 Kms against gravity is not the same as what you use
>> to put the same mass into orbit. That will change depending on
>> just how
>> you do it, none of the machines I've ever seen are 100% efficient,
>> not all
>> systems are equal, except in a physics classroom.
>
>The current launch trajectory of the space shuttle is highly
>inefficient. Instead for direct orbital insertion, they go to about
>98% of the speed required, drop down, release the fuel tank so that
>it falls into the Indian Ocean, and then pick up speed again. If
>they carried the fuel tank into orbit with them, it would take LESS
>fuel!

Yes but then they would have to deal with a large mass that is
shedding debris, what are they going to do with it? Now before you
start saying they should boost it into a stable orbit and use it as
the basis of a some kind of orbital construction, remember they need
to justify all their actions and can not be building something just
for the sake of building it.

>By the way, NASA will launch the external tank for free, if you can
>retreive it, make sure the rapid decay of the insulation coating
>doesn't rain anywhere near existing sattelites or the shuttle
>itself,
>and move it into a stable orbit. That's 30 tonnes of space-rated
>Aluminum alloy, shaped as two tanks both space-rated at over 1
>atmosphere of pressure, with hatches at each end, and an intertank
>structure containing a beam strong enough to carry the entire
>load of the solid rocket boosters, and a strongback capable of
>sustaining the entire load of both boosters and the main engines. If
>they go for direct orbital insertion, the tanks would contain about
>1000 kg of leftover Hydrogen and 10000 kg of leftover Oxygen - very
>valuable property for free, if you can get it. How's that for cheap
>orbital insertion?

The Russians have an even better deal, one complete, functional (sort
of, okay, sometimes, in a way) space station that I'm sure they
would sell you for a really good price, if you would only take over
the running costs. Sitting in the middle of the Australian outback,
dieing of thirst, it does you no good to know that 1000 Kms away, at
home you have a fridge full of chilled water. If you can't get to
it, then it may as well not be there.

You are working at your homebuilt particle accelerator in your garage
(hey, this is a "what if" and that means you can have what ever you
want) when you hit on a really cheap way to get to orbit. You can
get it down to $1USD per kilogram, so what next? It would be really
easy to make yourself rich in the LEO satellite business but if you
are aiming for a real habitat that could house an entire city then
the LEO business is starting to look attractive, you will need to the
money. Even if you ignore launch costs, then building a large scale
structure in orbit is a very expensive undertaking. Are you going to
build from scratch or use the hollow asteroid idea or perhaps you
will want to move to a planet and do the domes city thing. None of
them is easy or cheap. We are at an interesting place at the moment,
where there is a number of possibilities that may get us to orbit at
a reasonable cost but that just makes the next step look even
bigger. By the way, unless you build everything here on Earth and
then ship it into orbit, anything you build to house a population
could be considered a violation of the UN treaty on the use of space
and celestial objects.

>> You have left out the need to get the land to build the thing and
>> then there is the problem of environmental impact and other
>> political concerns.
>>
>You're right, I did. OK, environmental impact first. This can be
>divided up into several categories:
>- environmental destruction due to building the project. Most of the
>sites that would be suitable for building a railgun(or a lightcraft,
>for that matter)would have areas where it would not be convenient to
>build a road. A mountain peak that had a fairly level summit might
>have sheer cliffs all around. Much of the construction equipment
> and parts might need to be transported by heavy-lift helicopter.
> There are some fragile ecosystems to consider, and certain
> mountaintops are
>sacred to native peoples. But there are many, many routes to
>consider if we are looking at routes of less than 200km. How many
>marshlands were paved over to build Kennedy Space Center? How many
>fragile desert ecosystems have gone extinct due to Edwards Air Force
>Base? Has it made a difference? Has anyone noticed?
>- atmospheric pollution due to system operation: clearly, the
>conventional rockets are the big losers here. With
>electromagnetic launch, it is as clean as the system which generated
>it (coal, nuclear, hydroelectric, solar, etc).
>- noise pollution: again, conventional rockets are the big loser
>here. There is a sonic shock wave in either case: along the railgun
>the shock wave is broken by the shape of the solenoid rings. There
>is no such baffle for rockets. They also produce a noise from their
>controlled explosions that literally shakes the earth.
>
>Now, political considerations. If the railgun needs to be less than
>160 km long to be effective, there are a huge number of sites around
>the world that are potential candidates.

Sorry? 160 Kms long? I thought you were talking about a much longer
system, at 160 Kms you would need something like 20 Gs to reach orbit
although only for 30 seconds or so. Another point, a rail-gun and a
coil-gun or mass driver are not the same thing and work in a
different manner. If you have solenoid, you are not using a rail-
gun. This still is something that I'm having trouble with. I
understand that you are talking about a set of rings that will
generate a magnetic field that will pull or push the projectile but
unless they are very close together you are going to have a changing
acceleration as the distance from the ring changes, yes I know you
said that the power level would change to compensate but if the rings
were set a metre apart the power needed would not be that big
(relatively) but if they were say 1 kilometre apart then you would
need an enormous amount of power and then you also have the problem
of confining the field to stop it from playing havoc with things in
the area or else have a very large exclusion zone.

>Turkey is such a
>mountainous country, there are several places within it that could
be
>used as launcher sites, in several different directions. Australia
>possesses a large meteor crater in the middle of the Northern
>Territory, and the south rim (near Alice Springs) looks attractive;
>most of its launch trajectory would be in a roughly polar orbit,
over
>the Pacific. Australia also has a nice, long mountain range in
>northeast Queensland and another along the coast of New South
Wales.

I know it well, Canberra is located in the middle of it but not near
the coast but I think you should have a second look at your map and
check the height of the mountains around here, the best you can do is
just 2228 metres and as for the rest of the country, well this is one
of the flattest countries on Earth, mind you it is also one of the
largest and the only one to have an entire continent to itself.

>Columbia may own day become known for more than coffee and cocaine;
>the mountains on its west coast offer particularly attractive
>trajectories. There are tons of sites available, with trajectories
>that do not cross over other political jurisdictions.
>Probably the biggest political consideration is: what if there is an
>accident? What if it fails? The US space program was not prepared
>for Challenger; the political fallout cost NASA years of lost time.
>If a lightcraft were to suffer a catastrophic loss of power, the
>craft would plummet (not designed to glide).

A large parachute in the nose would fix that.

>If a railgun were to
>suffer loss of power to one of its rings, it would probably still
>function; if there were a catastrophic loss of power, it would
depend
>on the position of the projectile within the gun. Near the
beginning
>(while still on the maglev track) would probably not lead to
>catastrophe. The first few kilometers of the railgun assembly would
>probably be the most dangerous, where the rings are placed close
>together; catastrophic loss of power would likely mean a crash, and
>the partial or complete destruction of several rings. Near the end
>of the railgun, momentum and lift would likely be enough to keep the
>projectile going to an emergency landing strip. The worst-case
>scenario is not as bad as the Challenger disaster: it is easier to
>mass-produce solenoid rings than it is to build a new space shuttle.
>

Take a look at the message from Al Globus and my reply, what about
people who decide to blow it up?

>
>In terms of total area, the US space program takes up a larger
>footprint than my proposal. A strip 1km wide by 160 km long is
>equivalent to a 10km/16km military base; the Kennedy Space center is
>comparable in area.
>

Maybe but they are not compelled to have a particular place, what
happens if one or more people in the middle of your planned path
decide they don't want to sell or want a lot more than you can pay?

>You're right. No government will build it unless it is politically
>expedient. No private citizen or corporation would build it unless
>it would turn a profit - which it would. Wish I had Bill Gates'
>money!
>
>:) ed

Mr Gates money is mostly a paper fortune, that is it is not cash but
shares in companies, I doubt that even he could finance your project
even if he bankrupted himself to do it. Still it is a nice thought.

Darren Brown
Canberra Australia

--- In spacesettlers@egroups.com, "Darren Brown" wrote:
> >ed: If
> >they carried the fuel tank into orbit with them, it would take
LESS
> >fuel!
>
> Yes but then they would have to deal with a large mass that is
> shedding debris, what are they going to do with it? Now before you
> start saying they should boost it into a stable orbit and use it as
> the basis of a some kind of orbital construction, remember they
need
> to justify all their actions and can not be building something just
> for the sake of building it.
>

NASA has some guidelines in place for this. For one thing, they do
not want to have to modify the tank in any way. It must require a
bare minimum of astronaut attention ie little or no EVA time. It
should take up little or no payload bay space. The salvage must put
the tank in a stable orbit, deal with the external insulation, and
turn the tank into useable hardware ie power, communications,
guidance, maneuvering, and propulsion systems on-board.

There has been lots of discussion about adding an aft cargo carrier
(ACC) to the nadir of the tank; Martin Marietta can make it without
retooling anything. It is within the shuttle system's excess weight
allotment, and can come in a variety of configurations. However, for
any tank salvage system to be successful, it should not have to rely
on the NASA green light to add an ACC.

There is cargo space in the intertank, but cargo must not place a
load on the LOX tank, the LH2 tank, or the SRB beam, nor provide a
direct connection from the LOX tank to the LH2 tank. It must fall
under certain weight requirements, as well (I believe 5 tonnes
maximum). That's not very much mass, but hey, NASA is going
for "faster, cheaper, better" now anyway, right?

There is enough fuel left over in the external tank to take it to a
stable orbit, if the shuttle goes for direct orbital insertion, and
if the tank has its own propulsion and guidance systems. There would
even be some fuel left over.

One external tank with a little extra fuel all by itself itsn't worth
much, at least not on a first or second mission. Several of them,
each scavenged for fuel later, would lead to a large fuel depot in
orbit. Recovering fuel that would already be near or at the top of
the gravity well and which would otherwise be wasted is a very
worthwhile idea. In-flight refueling would save the international
space station effort and Mir millions of dollars, as well as
extending the life of other existing sattelites. Insurance premiums
would also drop, as the sattelites would have longer lifespans.

> >very
> >valuable property for free, if you can get it. How's that for
cheap
> >orbital insertion?
>
> The Russians have an even better deal, one complete, functional
(sort
> of, okay, sometimes, in a way) space station that I'm sure they
> would sell you for a really good price, if you would only take over
> the running costs.

The Hydrogen tank inside the external tank measures over 8m diameter
by over 35m long. You could probably fit Mir inside. BTW, it is a
shame what is happening to Mir. It was designed for only a few years
in space...what has it been now, twelve? Yeoman service. I will be
very sad if they have to bring it down. Those operating costs could
be brought down, with an in-orbit gas station...

> Sitting in the middle of the Australian
outback,
> dieing of thirst, it does you no good to know that 1000 Kms away,
at
> home you have a fridge full of chilled water. If you can't get to
> it, then it may as well not be there.
>

Which is exactly where we are, with expensive launch costs.

> You are working at your homebuilt particle accelerator in your
garage
> (hey, this is a "what if" and that means you can have what ever you
> want) when you hit on a really cheap way to get to orbit. You can
> get it down to $1USD per kilogram, so what next? It would be
really
> easy to make yourself rich in the LEO satellite business but if you
> are aiming for a real habitat that could house an entire city then
> the LEO business is starting to look attractive, you will need to
the
> money. Even if you ignore launch costs, then building a large
scale
> structure in orbit is a very expensive undertaking. Are you going
to
> build from scratch or use the hollow asteroid idea or perhaps you
> will want to move to a planet and do the domes city thing. None of
> them is easy or cheap. We are at an interesting place at the
moment,
> where there is a number of possibilities that may get us to orbit
at
> a reasonable cost but that just makes the next step look even
> bigger. By the way, unless you build everything here on Earth and
> then ship it into orbit, anything you build to house a population
> could be considered a violation of the UN treaty on the use of
space
> and celestial objects.
>

Building things out of salvaged manmade objects (ie Mir, shuttle
external fuel tanks) would not break the treaty. And remember, a
treaty is only honoured if it is enforced.

> >Now, political considerations. If the railgun needs to be less
than
> >160 km long to be effective, there are a huge number of sites
around
> >the world that are potential candidates.
>
> Sorry? 160 Kms long? I thought you were talking about a much
longer
> system, at 160 Kms you would need something like 20 Gs to reach
orbit
> although only for 30 seconds or so.

A strictly cargo carrying mass driver would be about that long; the
longer ones are for humans (1050km for LEO, 2400 km for Earth-Moon
escape velocity). Not every mass driver needs to be the maximum
length.

> Another point, a rail-gun and a
> coil-gun or mass driver are not the same thing and work in a
> different manner. If you have solenoid, you are not using a rail-
> gun. This still is something that I'm having trouble with.

You see, this is what I get for shooting my mouth off before I know
exactly what I'm talking about. I mean a mass driver. Check out
http://www.ssi.org/research.html , the section on mass drivers - some
of their experimental ones could acheive 1800g.

> I
> understand that you are talking about a set of rings that will
> generate a magnetic field that will pull or push the projectile but
> unless they are very close together you are going to have a
changing
> acceleration as the distance from the ring changes, yes I know you
> said that the power level would change to compensate but if the
rings
> were set a metre apart the power needed would not be that big
> (relatively) but if they were say 1 kilometre apart then you would
> need an enormous amount of power and then you also have the problem
> of confining the field to stop it from playing havoc with things in
> the area or else have a very large exclusion zone.
>

The beauty of a solenoid is that it concentrates the magnetic field.
Outside the structure, the fields created by opposite sitdes tend to
cancel each other out, but inside, the field adds together from all
sides. The larger the solenoid, the greater the magnetic flux
density... and I am talking about devices perhaps 50m or more in
diameter. Larger structures means that the spacing would be greater,
and rings would not need to be evenly spaced, but could be spaced
further and further apart; materials cost would also increase
proportional to square of the radius, so it makes sense to have
sm,aller rings spaced closer together at the start, with larger and
larger rings further along. As I mentioned previously, there is a
lot of math that I haven't done on this idea yet.

> >Turkey is such a
> >mountainous country, there are several places within it that could
> be
> >used as launcher sites, in several different directions.
Australia
> >possesses a large meteor crater in the middle of the Northern
> >Territory, and the south rim (near Alice Springs) looks
attractive;
> >most of its launch trajectory would be in a roughly polar orbit,
> over
> >the Pacific. Australia also has a nice, long mountain range in
> >northeast Queensland and another along the coast of New South
> Wales.
>
> I know it well, Canberra is located in the middle of it but not
near
> the coast

I guess that just goes to show that everything is relative. Canberra
is about 100-150km from the coast as the crow flies; you do not
consider yourself near the coast relative to the other side of the
mountain range, south of Wollongdong for instance. I live in
Calgary, Canada, and the nearest coastline is 700-800km away.

> but I think you should have a second look at your map and
> check the height of the mountains around here, the best you can do
is
> just 2228 metres and as for the rest of the country, well this is
one
> of the flattest countries on Earth, mind you it is also one of the
> largest and the only one to have an entire continent to itself.
>

The thickest atmosphere is in the lowest 1000m (ideally, you would
want the highest mountains you could get, as close to the equator as
possible, but the Himalayas and Turkey have all sorts of messy
jurisdictional headaches). My Atlas isn't very good. How high is the
southern rim of the crater in the Northern Territory?

> >If a lightcraft were to suffer a catastrophic loss of power, the
> >craft would plummet (not designed to glide).
>
> A large parachute in the nose would fix that.
>

Good point. Got any good lightcraft links?

>
> Take a look at the message from Al Globus and my reply, what about
> people who decide to blow it up?
>

Nasty business, that. We also have our eco-terrorists in Canada, who
somehow decide it would be good for the environment to blow up oil
pipelines. A pipeline is a good analogy; large sections of it are
aboveground but isolated, especially further north (can't bury it in
permafrost).

There are also many similar examples in the railroad industry,
worldwide. (hey.... doesn't Chile have a railroad along the top of a
mountain ridge? More economical to use existing infrastructure...)

NASA gets around this by having launch facilities on a military
base. SeaLaunch uses secure manmade facilities surrounded by lots of
ocean. The Baikonir Cosmodrome is on a military base.

> >
> >In terms of total area, the US space program takes up a larger
> >footprint than my proposal. A strip 1km wide by 160 km long is
> >equivalent to a 10km/16km military base; the Kennedy Space center
is
> >comparable in area.
> >
> Maybe but they are not compelled to have a particular place, what
> happens if one or more people in the middle of your planned path
> decide they don't want to sell or want a lot more than you can pay?
>

When this happens to government, they simply expropriate. It
happened to my family when the city of Edmonton expanded south. It
happened both in Australia and in Canada to our respective aboriginal
people, although I think perhaps Australia has a better track record
on that count.

As for private industry, the railroad barons of the 19th century USA
faced a similar problem. There were multiple possible routes they
could take, and a railroad through an existing town would increase
that town's economy tremendously. But that meant securing the route
to and from the town, as well as being able to protect the route.
They played towns off one another, and put pressure on the people on
the route (if you don't sell, then we will put the line through town
X instead of town Y, and your land will be worthless, etc).

If there were multiple possible mass driver sites, presumably one
would play off the people at each of the different sites against one
another, the way the old railroad tycoons would play off one town
against another, or the way that Olympic bids are conducted today.

(Mark Twain (Samuel L. Clemons) wrote a story called The Adventures
of Tom Sawyer. In one part of the story, Tom is being punished by
being forced to whitewash a fence. He convinces a younger boy that
it is fun and lets the boy do the work, in exchange for paying Tom.
He soon has boys out-bidding one another for the "fun" of
whitewashing the fence.)

The probability of multiple adequate sites would ensure that a
suitable candidate could be found. The economic spinoffs associated
with such a site are enormous, and should be enticement enough to
attract competeing bids. I mentioned possible sites in Australia,
Turkey, Canada, Columbia; there are also other possible sites.
Venezuela, for instance, or Ethiopia, or Iraq.

:) ed