Nanotubes, Yarn Twist, Nanoscale Friction

Hi Uncle Al,

While I read that an earthly Space Elevator would be problematic, I
was reading that a lunar Space Elevator could be feasible.

http://www.e4engineering.com/story.a...sj5d&id=218937

Lunar gravity is much lower, affording a wider choice of tensile
materials. Lunar orbital space is not as crowded and cluttered and
earth orbital space. A lunar Space Elevator might allow easier access
to the Moon. I was also reading that existing spacelaunch vehicles
might be suitable for trips around the moon:

http://www.msnbc.msn.com/id/6558855/

If you can loop around the moon, perhaps it's so much farther a leap
to dock with a space elevator there.

sanman wrote:

Hi Uncle Al,

While I read that an earthly Space Elevator would be problematic, I
was reading that a lunar Space Elevator could be feasible.

http://www.e4engineering.com/story.a...sj5d&id=218937

Lunar gravity is much lower, affording a wider choice of tensile
materials. Lunar orbital space is not as crowded and cluttered and
earth orbital space. A lunar Space Elevator might allow easier access
to the Moon. I was also reading that existing spacelaunch vehicles
might be suitable for trips around the moon:

http://www.msnbc.msn.com/id/6558855/

If you can loop around the moon, perhaps it's so much farther a leap
to dock with a space elevator there.

The moon revolves every 28 days or so. What is the radius of that
selenosynchronous orbit? Add terrestrial perturbations. L1 is not
stationary with respect to the lunar surface. As for the second link,
"stupid pet trick."

A Saturn MLV-V-3 booster ringed with eight Space Scuttle SSBS (no
recycle packages) - use once and toss - would have a LEO boost payload
of 700 tonnes net (compared with the Space Scuttle's 25 tonnes maximum
considering "safety" add-ons). 700/25=28. Price to LEO for large
objects (100% self-contained pocket nuclear submarine plus
consummables) would plunge. Three such launches, exceeding the summed
maximum payload of the whole Space Scuttle program over its entire
projected lifetime had it worked, would give you an installed
permanent moon base in proven hardware.

http://www.mazepath.com/uncleal/nasa3.htm

Why dream about bull**** when reality is available at a discounted
price off the shelf? One could upgrade the Saturn's engines - it has
been almost 40 years. That is your throw weight engineering
tolerence. Also note that the Saturn's aluminum skins were soldered,
fer chrissakes. We can now weld aluminm/scandium - stronger, lighter,
pioneered by the Russians for ICBMs. Still more net payload... and
the blueprints are already drawn and certified. That alone saves
about $20 billion, 10 years, and a major Congressional probe into
corruption and failure.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

"Uncle Al" wrote in message
...
sanman wrote:

Hi Uncle Al,

While I read that an earthly Space Elevator would be problematic, I
was reading that a lunar Space Elevator could be feasible.

http://www.e4engineering.com/story.a...sj5d&id=218937

Lunar gravity is much lower, affording a wider choice of tensile
materials. Lunar orbital space is not as crowded and cluttered and
earth orbital space. A lunar Space Elevator might allow easier access
to the Moon. I was also reading that existing spacelaunch vehicles
might be suitable for trips around the moon:

http://www.msnbc.msn.com/id/6558855/

If you can loop around the moon, perhaps it's so much farther a leap
to dock with a space elevator there.

The moon revolves every 28 days or so. What is the radius of that
selenosynchronous orbit? Add terrestrial perturbations. L1 is not
stationary with respect to the lunar surface. As for the second link,
"stupid pet trick."

A Saturn MLV-V-3 booster ringed with eight Space Scuttle SSBS (no
recycle packages) - use once and toss - would have a LEO boost payload
of 700 tonnes net (compared with the Space Scuttle's 25 tonnes maximum
considering "safety" add-ons). 700/25=28. Price to LEO for large
objects (100% self-contained pocket nuclear submarine plus
consummables) would plunge. Three such launches, exceeding the summed
maximum payload of the whole Space Scuttle program over its entire
projected lifetime had it worked, would give you an installed
permanent moon base in proven hardware.

http://www.mazepath.com/uncleal/nasa3.htm

Why dream about bull**** when reality is available at a discounted
price off the shelf? One could upgrade the Saturn's engines - it has
been almost 40 years. That is your throw weight engineering
tolerence. Also note that the Saturn's aluminum skins were soldered,
fer chrissakes. We can now weld aluminm/scandium - stronger, lighter,
pioneered by the Russians for ICBMs. Still more net payload... and
the blueprints are already drawn and certified. That alone saves
about $20 billion, 10 years, and a major Congressional probe into
corruption and failure.

Or - actually build Sea Dragon. 550 tons per launch.

Tony S.

Tony wrote:

"Uncle Al" wrote in message
...
sanman wrote:

Hi Uncle Al,

While I read that an earthly Space Elevator would be problematic, I
was reading that a lunar Space Elevator could be feasible.

http://www.e4engineering.com/story.a...sj5d&id=218937

Lunar gravity is much lower, affording a wider choice of tensile
materials. Lunar orbital space is not as crowded and cluttered and
earth orbital space. A lunar Space Elevator might allow easier access
to the Moon. I was also reading that existing spacelaunch vehicles
might be suitable for trips around the moon:

http://www.msnbc.msn.com/id/6558855/

If you can loop around the moon, perhaps it's so much farther a leap
to dock with a space elevator there.

The moon revolves every 28 days or so. What is the radius of that
selenosynchronous orbit? Add terrestrial perturbations. L1 is not
stationary with respect to the lunar surface. As for the second link,
"stupid pet trick."

A Saturn MLV-V-3 booster ringed with eight Space Scuttle SSBS (no
recycle packages) - use once and toss - would have a LEO boost payload
of 700 tonnes net (compared with the Space Scuttle's 25 tonnes maximum
considering "safety" add-ons). 700/25=28. Price to LEO for large
objects (100% self-contained pocket nuclear submarine plus
consummables) would plunge. Three such launches, exceeding the summed
maximum payload of the whole Space Scuttle program over its entire
projected lifetime had it worked, would give you an installed
permanent moon base in proven hardware.

http://www.mazepath.com/uncleal/nasa3.htm

Why dream about bull**** when reality is available at a discounted
price off the shelf? One could upgrade the Saturn's engines - it has
been almost 40 years. That is your throw weight engineering
tolerence. Also note that the Saturn's aluminum skins were soldered,
fer chrissakes. We can now weld aluminm/scandium - stronger, lighter,
pioneered by the Russians for ICBMs. Still more net payload... and
the blueprints are already drawn and certified. That alone saves
about $20 billion, 10 years, and a major Congressional probe into
corruption and failure.

Or - actually build Sea Dragon. 550 tons per launch.

Tony S.

Hi,

What do you think about electromagnetic gun launch to space?

This is the notion that a 10 km track at almost survivable acceleration
launches a pod to just beyond the edge of the Earth's gravity well.

This is theoretical, obviously, there have only been lab experiments and
test installations for a hundred years towards using electromagnetic gun
launch to space. Rocket launch has a much longer history.

Some issues are to do with electromagnetic switching of the power to the
coils of the coilgun to launch the cargo pod, with its associated reaction
mass and modular ion thruster, solar sail array, or other propulsion device
that would only need nominal thrust because it is launched from the ground
out past Earth's gravity well, or any point between. So anyways besides the
pulsed-power switching, then there are theoretical, not limits, just issues,
about hypervelocity performance for the few seconds that the pod is in the
atmosphere as it flies into space at Mach 30.

That's a good idea, heavy lift, except one of those boosters might fail,
explosively, somewhere in the middle of the air, which would be difficult to
repair in flight from the ground. With the ETOMD, Earth to Orbit Mass
Driver, you can work on it in sandals, shorts, and a tanktop. Hell you
could smoke around it, a six mile track of energizing magnetic coils, there
are no volatile chemicals. It might be a good idea to not have a pacemaker
or ferric body piercings around it, with the many Henries.

That's not to say chemistry doesn't have a place in the electromagnetic gun
launcher, for example superconductor is a molecular compound.

It might cost more than strapping together those modular boosters, and then
when it was done it would cost orders of magnitude less, and instead of a
moon base made with hundreds of tonnes of stuff, thousands of tonnes of
stuff. Save the high reliability low-acceleration rocket boosters for soft,
squishy people.

In terms of materials, high temperatore superconductor is really going to
allow a lot of inroads: think high efficiency transformers and even
electric motors, cooling channels on the silicon, all kinds of stuff. I
apologize to sci.materials, I'm ignorant about the single or multi walled
carbon nanotubes.

ETOMD - ten tonnes per launch, at around five or six hundred bucks each.
Well, actually it would be around twelve hundred.

As a big science project, its development would lead to advancements in the
high power magnets, and cheap access to space is its own reward.

Hey, if this is "sci.space.policy", please refrain from having any
discussion of anything that is not specifically about space exploration
policy. That is to say, I'm angry to see any reference to contemporary
politics, damn crooks.

So anyways, electromagnetic gun launch is a little nearer to believable on
the scale compared to a 200000 kilometer by 1 centimeter carbon composite
cable, particularly one hanging off into space.

Boom! What was that? Ten tonnes to the moon. Boom! It's much quieter
with the ionizing phase array.

Ross F.

Ross A. Finlayson wrote:


What do you think about electromagnetic gun launch to space?

snip


So anyways besides the
pulsed-power switching, then there are theoretical, not limits, just issues,
about hypervelocity performance for the few seconds that the pod is in the
atmosphere as it flies into space at Mach 30.


Yep.

Just issues.

LOL

"Ross A. Finlayson" :

Hi,
What do you think about electromagnetic gun launch to space?

This is the notion that a 10 km track at almost survivable acceleration
launches a pod to just beyond the edge of the Earth's gravity well.

Always try and do the math first:
Distance = 0.5 * Acell * Time^2 : Speed = Acell * Time. And yes, I am
dumb we are reaching the limits of my knowledge here

For a 10 Km track at 50G which I believe (yes I can be wrong) is the max a
human will survive if floating in a neutral density solution will be covered
in less than 7 seconds and the exit speed = 3130 meters per second.

A long track will help along with the lower acelleration, but watch out the
real human limts at each level of acelleration.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

In sci.space.policy Earl Colby Pottinger wrote:
"Ross A. Finlayson" :

Hi,
What do you think about electromagnetic gun launch to space?

This is the notion that a 10 km track at almost survivable acceleration
launches a pod to just beyond the edge of the Earth's gravity well.

Always try and do the math first:
Distance = 0.5 * Acell * Time^2 : Speed = Acell * Time. And yes, I am
dumb we are reaching the limits of my knowledge here

For a 10 Km track at 50G which I believe (yes I can be wrong) is the max a
human will survive if floating in a neutral density solution will be covered
in less than 7 seconds and the exit speed = 3130 meters per second.

A long track will help along with the lower acelleration, but watch out the
real human limts at each level of acelleration.

AIUI, 30G is about the max before someone immersed in water will stop the
test.
An interesting coincidence is that immersed in water, over a fairly wide
band of accelleration (IIRC 12-25G) the maximum time that 'motivated
voulanteers' can take adds up to a delta-v of 10Km/s or so.
25G to 10Km/s is 40 seconds, or 200Km.

The problem that then arises is that the sectional density of the launched
pod needs to be quite high, so that it does not slow down appreciably
when it punches through the atmosphere.

Even if you can get the exhaust at 7Km, then it's still a lot of mass
of atmosphere to push past.

You're at best looking at a very, very large (or at least long) vehicle.

In article ,
Earl Colby Pottinger wrote:
Always try and do the math first:
Distance = 0.5 * Acell * Time^2 : Speed = Acell * Time.

Or more directly: velocity^2 = 2 * acceleration * distance .

Even with zero allowance for air resistance, catapulting to orbital
velocity requires about 3500 G-km, and catapulting to escape requires
about 6000 G-km.

For a 10 Km track at 50G which I believe (yes I can be wrong) is the max a
human will survive if floating in a neutral density solution will be covered
in less than 7 seconds and the exit speed = 3130 meters per second.

Even 50G is pushing it: existing experimental results seem to top out at
31G, in water immersion with optimal posture (which isn't flat on your
back, it turns out -- you want the upper body sloping up at about 30deg,
sort of a lawn-chair position).


By the way, don't forget *deceleration* forces due to air drag. Drag is
classically 0.5 * Cd * frontalarea * airdensity * velocity^2 . Let's take
the orbital case, assuming a projectile 2m in diameter (big enough to hold
passengers in near-prone position) with a mass of perhaps 5t. Sea-level
air density is about 1.2kg/m^3; let's assume that the exit end of the
catapult is at substantial altitude so it's 0.8kg/m^3. Subsonic drag
coefficient for a blunt nose with rounded corners -- nothing pointed is
going to survive! -- is around 0.2, so make a wild guess that it's 0.4
at hypersonic speeds. Dividing drag by mass gives deceleration, and for
those numbers, it's a mere... 718 G!

Oops. "Houston, we have a problem." If you really push hard to optimize
all of the parameters, you might perhaps be able to cut that by a factor
of as much as ten. And that's still too much. An orbital catapult's
payloads will not be manned, period.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Earl Colby Pottinger wrote:

"Ross A. Finlayson" :

Hi,
What do you think about electromagnetic gun launch to space?

This is the notion that a 10 km track at almost survivable acceleration
launches a pod to just beyond the edge of the Earth's gravity well.

Always try and do the math first:
Distance = 0.5 * Acell * Time^2 : Speed = Acell * Time. And yes, I am
dumb we are reaching the limits of my knowledge here

For a 10 Km track at 50G which I believe (yes I can be wrong) is the max a
human will survive if floating in a neutral density solution will be covered
in less than 7 seconds and the exit speed = 3130 meters per second.

A long track will help along with the lower acelleration, but watch out the
real human limts at each level of acelleration.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

There are copious discussions on these groups about the idea.

http://www.google.com/groups?as_oq=c...=sci.space .*

The people-mover is some 300 kilometers of track, and it's gentle and less than
2G.

Ian here, Ian Stirling, and I were talking about it before with others, on that
thread started by Dez Akin, "Coilguns and EM Launchers", basically it appears
to involve supermodels. Of note is the pulsed power considerations and the
January of odd-numbered years' of IEEE Transactions on Magnetics, where that
issue every two years is devoted to EML. Many papers have been written by
adequate sliderules and egg and propeller heads detailing much of the
trajectory information, including rocket scientists from NASA.

One fellow claims to have a 11 km/s design, a paper from the late 90's claims
it could be built from "off-the-shelf" components.

The 10 kilometer track is not very surviv(e)able unless you only go into orbit,
not out of the gravity well. Then, if you go into orbit the pod needs a kick
motor to regularize the orbit, else it would be an incomplete orbit and impact
the Earth.

Some discussions about the hardware include many thousands of coils, and
perhaps an evacuated launch tube. My idea is to have ionizing radiation out of
the snout of the thing to excite the air thus that it is thinned in the launch
path by the ray gun, or perhaps some kind of plasma burst charge thingie, that
trailblazes through the atmosphere for the pod. Otherwise the pod is just a
torpedo, basically, figures have from ten to ninety percent of the pod being
ablative mass, it could be more or less. I think it would be good to have
standardized two, ten, and forty tonne pods, from the same launcher, from
having a big dial in the control room with three settings: 2, 10, and 40, next
to the big red button marked "launch."

About the pod, it needs some avionics, the ablation mass, perhaps a
self-destruct or reentry system, and then it's basically a cargo crate.
Because they wouldn't be designed for carrying people necessarily, the parts
could be mass produced more often, leading to economies of scale after and
during the suitability tests of the theoretical Earth to space mass driver
launching hundreds or thousands of tonnes per day to space.

Regards,

Ross F.

In sci.space.policy Henry Spencer wrote:
In article ,
Earl Colby Pottinger wrote:
Always try and do the math first:
Distance = 0.5 * Acell * Time^2 : Speed = Acell * Time.

Or more directly: velocity^2 = 2 * acceleration * distance .

snip
at hypersonic speeds. Dividing drag by mass gives deceleration, and for
those numbers, it's a mere... 718 G!

Oops. "Houston, we have a problem." If you really push hard to optimize
all of the parameters, you might perhaps be able to cut that by a factor
of as much as ten. And that's still too much. An orbital catapult's
payloads will not be manned, period.

On earth, it's hard to make the case.

The only possible reason I can think of would be for really massive
pods, your 718G figure for 5 tons sounds within an order of magnitude
of what I got.
That's maybe 1 ton/meter^2 of pod.
If you raise that to 25 tons/meter^2, then that goes down to about 30G,
which is more or less handleable.

The problem then arises that this is a pod of at least a hundred tons,
probably with over a hundred passengers.

The only way I can see this being possible in the future would be if
(for any reason) space elevators turn out not to be practical, and
electromagnetic accellerators turn out to be the cheapest way to get
stuff into orbit.

This would be a 'steerage' class of passenger transport to orbit.