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Magnetic Space Launches
DiZNoG writes "This CNN article discusses NASA experimenting with the idea of using Mag-Lev technology to launch payloads into space. Mentioned in the article is that the U.S. Navy is working on the technology for it's aircraft carriers to launch fighters. Unfortunately the NASA project is horribly underfunded ($30,000) for research. Cool technology, let's hope that the Navy research gets us a step closer to not burning all that Oxygen and Hydrogen to get to space...
weird i just saw this on a discovery documentary like 5 minutes ago... neat
The More Knowledge you have the Luckier you Get- J.R. Ewing
left of the "" tag on the end of the article.
Although this technology is by far a better way to get payloads into space, all the energy used to create sufficient electricity to do so would make this method of launch just as costly as the previous. Mag/Lev is an excellent suggestion, after we make more breakthroughs in superconductivity and emf it will become a spectacular solution.
Of all the Universal Constants, here's one I know: Nice guys finish last
I'm wondering how much of the benefits of this is in the acceleration/speed they hope to achieve in a small space, versus the height they want to reach. I'm an idiot on the subject, admittedly (who's an expert, anyhow?), but which is more unrealistic, building an EM rail that reaches near orbit, or trying to accelerate 100s of tons verticaly to reach a high speed? (I'm still going to assume that they'll use rockets to reach orbit, and not 100% rely on the rail for the energy.)
Well, I don't think the *cost* of energy (in terms of dollars) really is the issue here. It is the amount of onboard fuel which displaces the amount of cargo you can take into orbit. And since fuel has weight, the more fuel you add, the more fuel you need to achieve orbit. So, earth-based electricity vs. vehicle based fuel really would be a plus.
I doubt they'll get very far with that much money, perhaps not even to the end of the maglev rail.
It's really sad what's happened over the years to the once mighty space program like the US had that was fuelled by imagination, both public and governmental. Now it's run by short-sighted penny pinching bureaucrats.
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I didn't want to leave this space blank.
http://www.dreamworld.com.au/
;)
Just turn the thing into a giant "Tower of Terror" to raise funds
-- Dan =)
let's hope that the Navy research gets us a step closer to not burning all that Oxygen and Hydrogen to get to space...
Yes, we must reduce emissions of deadly Dihydrogen Monoxide! It's already filling our rivers, streams and oceans, and has been found even in the ice of Antarctica! The time to act is now, people! Before our wells are full of this dangerous chemical!
If I remember a while back, I could have sworn I saw some sort of launch system in either a computer animation demonstration or in a game itself.
This idea would be interesting to apply into space as there is very little friction in space to slow things down. Why not make an addon on to the IIS to launch vehicles to Mars or Venus via this launch method? If the track was long enough it could go faster than convention rocketry. And in fact, less fuel would be needed on the vehicle since the mag-lev was the device that launched it.
Yeah, totally! I mean, the exhaust produced by burning oxygen and hydrogen is just so toxic and hard to use! I can't think of anything natural that can even utilize it.
Dragging people kicking and screaming into reality since 1996.
Why doesn't NASA take this one step further...
::Colz Grigor
Attach a long magnetic launcher to the ISS. This would allow us to take a satellite to orbit via the shuttle, attach it to the magnetic launcher, and then we wouldn't have to wait years to send probes to other planets. And when we're ready to visit Mars by the year 2020, we can use the ISS railgun and get there in one month instead of six...
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Maybe something like that would make an awesome NYC WTT memorial tribute? It'll never happen, but it'd be cool.
What's this new "relationships" button? More importantly, what purpose does it serve? Please explain!
There's probably a good reason against this. But why not have a rocket take off that drags a string behind it? And, say, take the string to the moon. Then you can have whatever that needs to go into space just climb the string/rope/whatever? And can it be used to generate electricity?
... this would only be feasible on planetary bodies lacking a substantial atmosphere, e.g., the Moon, where a mass drive would be the most effective way to transfer mined materials to an L point. I cannot think of a scenario where they'd launch anything from the surface of the Earth with any kind of mass drive. Space elevator, perhaps, mass drive, hell, no.
Comic - not!
Existence usually comes as a surprise (Idem)
But it's not really that much of an improvement. The energy needed to create the electricity sufficient enough to accomplice this feat would be the equivalent of sending it up via hydro/carbons or any other volatile gas. The idea of Mag/Lev being used to launch vehicles into space is a great suggestion, once we make more breakthroughs in superconductivity and emf, it will become a spectacular solution.
Of all the Universal Constants, here's one I know: Nice guys finish last
By using mag-lev for both takeoffs and landings, the Navy could presumably have takeoffs and landings on the same boat very close to each other, without the complexity of the current mechanical system. But, of course, mag-levs are useless for landings from spacee, since spacecraft usually don't have wings - and those that do can just use parachutes for losing speed.
Though I guess you'd have a hell of an "electro-magnetic signature".
pr0n - keeping monitor glass spotless since 1981.
Anyone know how long the rail would have to be to get a craft to Mach 2-3 with survivable acceleration? Perhaps one of those supersonic ramjets could take over at that point - they need to be supersonic to light up, don't they?
You'd still save shedloads of fuel - and increase payload, and thats the point, right?
When I were your age, all round here were fields...
More information can be found here.
These frequencies are suspected to cause resonaces in the metallic core of earth, which creates earth's magnetic field.
The energy payloads used before for mag-lev trains etc. are relatively small, so that gravitational e-m wave reflection and refraction consumes these energy amounts and they have no effect. For space launches however you need very much energy which won't be consumed completely. So the energy will add up over several launches over time and will increase the earth core resonace oscillation steadily. At low energy levels this will cause an increased number and stronger earthquakes. But if large payloads are used this is much more dangerous, because the oscillation will break apart earths silicate hull and earth will break in little pieces. The asteriod belt is suspected to be created by a planet breaking apart due to core oscillations. See Eisenberg/Pronellis works on this.
So I think we such think twice before using this.
Owner of a Mensa membership card.
Now, if they can use solar energy to fire that baby... That would be the shiznit!
Ligaguinggligagiggagoogoogwillgo
Whoa there, son. Y'all from the future? Let's use units we all understand: what's that work out to in bushels of cotton per hectare?
Hmmm, I can't help but think that if we ceased habitually using stone age units of measurement, then we might be able to stop pounding Mars with "landers" ;-)
If you were blocking sigs, you wouldn't have to read this.
The advantage here would be that you dont need to burn fuel to make the fuel move. You dont need to add extra weight to get started. Im not an expert, but i assume that the basic idea would be gather speed (not even necessarily vertically to begin with), and then launch it vertically. It needs to be vertical to escape the drag of the atmosphere as quickly as possible.
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This isn't a new idea but it's cool that NASA's working on it. They might need something like that with this budget crunch. I'm surprised they can even afford to play with just the idea :P
In remember in Final Fantasy 8 they used a combination of some big gun and mag-lev to launch ships into space. It was one of the cooler things in that game.
Based on what I've read so far, it really isn't realistic to expect something like the space shuttle to be placed into orbit 100% from an EM rail. However, I'd go back to those other unconventional designs, like a helicopter or a jet being used as a launch vehicle for something designed to go into orbit. Those are being pushed because the benefit is that they clear the lower, dense atmosphere, which is where a lot of fuel is said to be spent.
If you look at am EM rail as something not to completely launch a vehicle into orbit, but to clear the dense portion of the lower atmosphere (and maybe give it enough velocity to save fuel on acceleration), doesn't it make more sense? That is, an EM rail as part of a greater delivery system, and not the whole delivery system?
They want to reduce the fuel needed. Meaning the launch vehicles will have to do some thrust by themselves, but not nearly as much.
Also, some people have noted that g-forces would be a problem. Not likely, if we angle the vehicle at a 45-degree starting angle we drastically reduce the ammount of g-forces needed.
Another point, the maglev system is frictionless. The LV is at no time during the launch touching the track. You've seen bullet-trains, right? Same consept. This further reduces the work needed to launch a vehicle.
I do see this system working. It will probably be 10 years or so, but it will work.
Well, not so much in execution but in conception. MagLev space launchers (including some military application) were a fundamental part in "The Moon Is a Harsh Mistress" (Heinlein), and the space elevator was (IIRC) first mentioned in "Fountains of Paradise" (Clarke, but I'm a bit fuzzy on both title and author). Both of them ususally have their facts right, no matter what you think about their literary merits. ;-)
Regarding MagLev: "all" you have to do is reach 11.2 km/s outside the atmosphere, the direction of the launch is irrelevant. Using a completely straight launch rail, starting horizontally (you'll have to think about earth curvature here) will only result in having more atmosphere to punch through - you'll still end up in orbit (or way beyond). One of the ideas in the latter part of "The Moon..." was setting up such a "catapult" in the Himalayas, which would get quite a bit of the atmosphere out of the way (at the risk of having to fire those things across Japan and towards the US). Big disadvantage would be the sonic boom, though
Anyway, they don't need more money, they just need to read more google groups
I really hate Dan Patrick.
Indians developed anti-gravity propulsions eons ago! Info here Of course they didn't find spaceship yet.. but lets keep our fingers crossed:)
Oh, and by the way if you haven't know.. I am a real Martian! A proof!
let's hope that the Navy research gets us a step closer to not burning all that Oxygen and Hydrogen to get to space...
...We wouldn't want all the resulting water vapor polluting our atmosphere, and our poor mother earth.
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
No mam, Sci-Fi doesn't rot your brains out, it's educational!
is the temperature of fresh ox blood. I've often wondered if US weather reporters need to perform some sort of ritual to calibrate their thermometers...
What would we do with all that water :-)
This makes me feel REALLY old, but the EML technology research has been going on for over 20 years. I recall the 1990 High School CX debate topic very well and spent most of the year debating EML launchers (prototyped on Sandia National Labs railgun). We spent the summer in the library in New Mexico visiting Sandia and UNM to research our cases. They were already launching coffee can-sized payloads at that time.
Some of the EML experiments from the late 80s and early 90s were visited at a 95 IEEE pulsed power conference: here. Of course, it's been a HOT topic since pre-85, when the first IEEE pulsed power conference was held.
We've been at the brink of maglev space launches for the alst 20 decades. Maybe it'll happen tomorrow. Probably not. There's basically no money in this sort of solution for defense contractors, so it generally languishes in congressional committees when it comes time to fund...
Oh well. It would be cheaper, cleaner, safer, and a whole helluva lot more fun at parties... but the same issues applied 20 years ago as today: it doesn't get funded b/c it's a public works-type solution to space. There's no money for Lockheed in something like that.
I didn't think they launched rockets exactly vertically. To get the orbital speed right, they go off at an angle - possibly after goign straight up for the most dense part of the atmosphere. I suppose for geostationary sattelites they don't need quite the rotation (and they need to go further up). Easier to explain with a picture, but no can do here.
This is why they like to launch from near the equator and always orbit in the same direction as the earth - you get a substantial boost (900 miles an hour according to Monty Python).
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a payload the size of most smaller sattelites or even a resupply module for the ISS could easily be flung into space with a railgun. The technology is proven, doesnt require special superconductors, and they have plenty of linear space at the cape to build a launch facility. The only thing they would need is a massive amount of electrical energy... like their own power plant.
In fact they were going to build such a launch system back in the 80's... I remember seeing it in a Pop-Sci magazine when I was in highschool.
Do not look at laser with remaining good eye.
Magnets schmagnets, lets just tie a long rope to the space station and we can climb up, like in gym class.
i think a feasible option would be to have energy beamed to a rocket via a microwave beam, which would be used to magnetically accelerate an amount of fuel out the back of a rocket, augmenting the normal propulsive power of the rocket engine, and thus requiring less fuel
Give the spacecraft a push, so you can wait until a certain hight before you turn on the rockets.
This is great if the rockets then actually ignite. Otherwise you would look kind of silly just throwing a spacecraft high into the air and then just watching as it drops :-)
By the way - to all those posts discussing geo-stationary orbit and earth escape velocity. You dont need to go all that way :-)
The space station is orbiting in approximately 400
km, and it is much cheaper to go there.
Kristian
He, who dies with the most toys, wins
I'm glad that maglev technology is finally being applied to something worthwhile. I'm getting really tired of seeing all the maglev rail transportation projects that never go anywhere (figuratively and literally)... :
That's all nice Cap'n Kirk, and I know that funding is tight and all.....
but the fact that even with tight funding they've only put $30,000 to the task tells me that nobody really ever expects this to pay off. Ever.
. Quit playing Monopoly with Bill. Switch to one of many non-Microsoft products today.
Kim Stanley Robinson wrote the RGB Mars book series, in which a space elevator was built on Mars. If I remember correctly (it's been a while since I read it), they modified the orbit of Deimos (or Phobos, I forget which) to geosynchronous, grabbed an asteroid or two from the asteroid belt, and had self-replicating robots build a factory there and start "spinning" diamond-filament threads.
By the time the asteroid got to Mars, most of the cable was already built, at which point it was anchored at a massive hold on the surface, and elevator cars were constructed to go up and down the elevator, using counterweights.
I believe that the problem of balancing it if you tried to "launch" something off the top of the platform was to simply give it a little push away, let it float off on it's own, and then use it's own engines to propel it.
Although it may seem a bit farfetched, I think that within the next decade, technology will allow us to realistically dream of doing this, although since we don't have nice-sized moons like Deimos or Phobos, we'd need to bring a bunch of asteroids in, which would make plenty of people on Earth rather anxious.
Still, it's a great theory, and perhaps some day we can get space elevators for cheap transportation into space.
Gawyn
Freedom of Speech?
"let's hope that the Navy research gets us a step closer to not burning all that Oxygen and Hydrogen to get to space..."
yerh, all those poultents preduced by burning
O and H...
goto think of the enviroment
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I think we can say that Nasa won't be doing anything terribly great in the near future, unless it's by pure luck/act of dog.
:P
:P
:)
We *so* *need* public corporations/conglomerations working on space travel and technology. A $30k budget.. For something like this.. Maybe they could buy a chip of ram for a supercomputer.
It's just so.. utterly laughable, yet so terribly sad. This is what we've become. We went to the moon. We planted a flag there. And now, politicians throw Nasa a few scraps and say, "Don't bother us."
I honestly don't expect to see anything happen with this on a $30k budget. Hell.. I know plenty of IT departments that get more than that!
Maybe we could get some of the open source idealism working in terms of space technology. Yes, I know, many people would shudder at the prospect of riding a rocket from someone's backyard (Not to mention the zoning difficulties I'm sure would be encountered..).. But hey, new frontiers aren't explored without risk to life and limb.
But really, there's got to be enough brains sitting around interested in this sort of thing that they could volunteer to come up with ideas on improving space tech.
Selling them to the government/Nasa might be the hard part, but frankly, they're a dead end in terms of space - the DoD wants Star Wars, and Nasa is playing with monopoly money (As in the pink and yellow stuff with the choo choo trains on it.)..
Once, just once, before I die, I'd like to go out to space without the need for a horrendous amount of math classes and an astronaut uniform.
It would be more efficient from a power/weight stand, but, It would be more harmful for the environment overall. The electricity would be generated on the surface of the earth somewhere and it would be most likely from coal. So this plan would be alot more harmful to the environment than Oxygen and Hydrogen.
http://slashdot.org/~Klerck/fans/
:P
You may want to just go ahead and foe-ize these guys.
Pardon my naivety but if a speed of over 7000 metres/sec is needed to achieve orbit, wouldn't the craft burn up?
And wouldn't it have to be going much faster than that off the launch track in order to be at 7000 m/s as it leaves the atmosphere?
It would be better to use the maglev to achieve the velocity necessary to cause a ramjet (or is it scram?) to ignite so as not to require the assistance of conventional jets, rockets and B52s to launch them.
A.K. Pseudoman (aka E.P. Northrup) wrote a bizarre science fiction novel in 1937 called 'Zero to Eighty: Being My Lifetime Doings, Reflections, and Inventions; Also My Journey Around the Moon' which has a large section in the back of photographs of (he claims working) models of railguns, and all sorts of technical arcana. In the book a railgun is used to launch a spacecraft... Clarke certainly knew of this book, as he metions it it the foreword of one of the Venus Prime books as one of his inspirations. I guess this is a little OT, but I hope interesting nonetheless.
Maybe we could put this on smaller things to launch from. Like say we put this thing on one of moons or large asteroids, establish a base, and let this thing efficiently get us back to Earth for the 4th of July every year.
Dry volume? How about cubic metres? That makes sense to me, but if you want hectolitres, knock yourself out at the many conversion websites.
Seriously, though. Your complaint about metric measurements assumes an American audience.
I'm either 5'11" (say, roughly 6') tall or 180.34cm. Now, which of those gives you a better mental picture of how tall I am? For scientific things, yes, powers of 10 work out real nice and all, but for everyday things, who the heck cares if you have to remember there's 12 inches in a foot... not that hard! The English units make a LOT more sense in everyday sorts of things.
I'm convinced that the ONLY reason "English" units make sense to you is because of your environment. I was always told my height in feet and weight in pounds, but my brother started through the Canadian school system 8 years after me, now that metric has become more pervasive. To him, measuring common distances in metres makes sense.
The only way to make a standard system of weights and measures intuitive to the common person is to make it ubiquitous. Scientific agencies like NASA should be leading the way. So, yes, it really should be dollars per kilogram.
And why the HECK have Star Trek producers ALWAYS used the incorrect pronunciation of kilometre?!? The same as any metric prefix like KILO-gram: it's KILO-metre, NOT kuh-LOM-etre!!! ARGH! That's one of my biggest pet peeves. Imagine saying kuh-LO-gram or cen-TIMI-tre!
Mozilla
Indeed, since O2 + 2H2 -> 2H2O an oxy-hydrogen motor doesn't look like harming the environment at all, unless it's the size of Madagascar. The winnage is in leaving the motor and its fuel supply Earthbound.
OTOH since launches don't happen continuously 24x7 the launcher could use solar/wind/tidal input and store it in superconducting accumulators for the next launch. These variable inputs are much more practical for powering rare events than for things like home heating or lighting. Win again.
Carter had the right idea when he was going to move us to metric. The entire rest of the world is on metric (save a few small countries and 1 large short-sighted country). Once you get use to thinking metric, it is easier for the bulk of what you do. Now the cost of doing business with the rest of the world is higher due to new labels, etc. Also, we just lost a multi-billion $vehicle/research due to rayguns descision. Hopefully, somewhere down the road, we will have no choice but to get with the program.
Um, you are totally ignoring the fact that the hydrogen and oxygen used for rocket fuel are either cracked out of water, or compressed out of the atmosphere. This being done by the prodigeous burning of petroleum products to run turbine compressors and produce electricity for Hydrolosis. In the end you pretty much equal out for either launch method.
I'm sure this was one of the technologies that you get in Sid Meyer's Alpha Centauri - so it must be workable!
...that slashdot posters like this one finally learn which usage of "it's" or "its" is appropriate in certain circumstances. You'd think that with at a bare-minimum 50% chance of getting it right that more geekly folks would not mess that kind of thing up.
You are making a fundamental mistake.
You are assuming gravity is a constant a= 9.81 m/s^2 at every height.
The formular s = 0.5 * a * t^2 works perfectly at managable heights around sea level, but the higher you go, the less that is true.
The formular s = 0.5 * a * t^2 comes from:
v(t) = v0 + a(t) * t
s(t) = s0 + Integrate(v(t))
or s(t) = s0 + v0*t + a(t)* 1/2 * t^2 - Integrate(1/2*a'(t)*t^2)
When a is a constant (which it isn't) the integral term would become zero because differating a constant becomes zero.
But since the pull of gravity drecreases at a rate the higher you go, a'(t) is a negative term, thus adding to the distance gained.
Imagine a cable running from the top of a 50 km tower into geo-stationary Earth orbit. Travelling on the cable is made through electromagnetic propulsion. Nasa is considering a 50 years timeframe for the space elevator to become real.
Maybe I'll go in space after all.
Men are born ignorant, not stupid; they are made stupid by education. Bertrand Russel
Not quite. First you need the energy of electricity to create the seperated hydrogen and Oxygen in the first place. Then you burn the hydrogen and oxygen at take off. With this new thing, you could skip the second step and use electricity at take off. That leaves the initial energy the same but cuts out the launch H and O consumption. I am always for converting things to electricity. That minimizes the technology we have left to improve. In other words we can focus on production technology as opposed to consumption technology.
whoa there...
:)
;) (o-DOM-eter, not O-DO-meter) Actually, since ki-LOM-eters come from France, and many accents in French are on the second syllable, I guess is makes sense! Parle vous FranCAISE? (sorry for the missing accent marks, and stuff...)
you're probably right that it's what you're used to, but my point is that the arbitrary English units are plenty fine, thank you. The primary benefit of metric is that everything converts nicely. Granted. I don't have a need to go converting inches to furlongs everyday, and if I do, I'm sure I can find the conversion rate somewhere.
I guess it's just an American independence thing then... we don't want the French telling us what system of measurement to use.
As far as KILO-meter (or metre, for you French) vs ki-LOM-eter, I guess it just sounds better. Probably related to spe-DOM-eter rather than SPEED-O-meter.
Have a great day! And, hey, we're just having fun here, right?
My other Slashdot ID is much lower.
This technology is a good example of NASA's insistence on developing unnecessarily complex technology. Rockets are perfectly adequate for launching into orbit; Maglev systems, and particularly maglev coupled with airbreathing systems, are fancy technology for its own sake.
A properly implemented rocket system can get launch costs below the $1000/lb claimed for this system. Heck, the Russians can get below that with expendable rockets!
There are more people looking at this for space launch than just a handful of guys in Huntsville launching model airplanes. And a lot more than $30,000 is being spent on it. These guys just did a little better PR (perhaps the fact that Huntsville is a short drive from CNN's facilities in Atlanta helped). Surely you don't expect CNN to have the latest (or even accurate) aerospace news, do you? Do they do an accurate job reporting about software? Go spend the money on (or find a library that has) a subscription to Aviation Leak and Space Technology, Janes, or better yet Journal of Spacecraft and Rockets if you really want to know what is happening.
U. of Washington EM Propulsion google cache (the original is either down or has been pulled for security reasons)
Gun Launched Satellites JH-APL (.pdf file)
Actually I suppose its your lack of foresight... NASA already has an idea based on accelerating electrons in the opposite direction to propel an object to a distant planet. I read about that on Discover magazine
Whatever. I thought it was funny.
I'm a 2000 man.
Pounds (of force and mass) are great units for working with rocket equations because you can "cheat" on your units and use specific impulse (measured in seconds... sort of) instead of using exhaust velocity. I also find it makes it easier to use gees as your unit of accel. than using m/s^2 with kg of mass and newtons of force.
Metric is great fun for calculating electrical problems (IMHO), but English is better for rocketry. In adv. physics, just pick whatever strange units (like measuring velocity in %c) make the equations come out easy then convert back when you are done. Units of measure are just a tool, no need to be a zealot about them.
This was done in the UK some years ago by Prof Eric Laithwaite of Imperial college, London. They even went as far as to put a magnetic catapult on a Royal Navy aircraft carrier to test it out. The good bit was that you could have the sledge return to its start point all on its own. The bad bit was that without the steam the track closed up in cold weather. Prof E. R. Laithwaite had a bit of a bee his bonnet about electro-magnets. Try and get a copy of "The linear motor and its application to tracked hovercraft" or "Propulsion without wheels"
Wasn't there something like this involved with those skateboards in Back to the Future? Once this technology advances enough, why not just build it right into the shuttle? Then we have no need for the huge launcher...
This space available at a low monthly rate...
available at Amazon which deals with a number of multimode transportation ideas:
Many ideas have been thrown around for using this technology on the moon for sending things to mars. On the moon, with the gravity factor 1/6th of it on earth, it would be a lot easier to send stuff out into space. Also you could set a huge long rail using all the space you want. But of course we have to get the materials for that to the moon. Guess we should build one here, first.
Those are interesting calculations. Now try this. If you just want to replace the first stage, then how long does the track need to be? Assume that the launch starts off horizontal, and then bends through an arc to over 45% toward vertical. And that you are replacing only the first stage. How long does the track need to be? How high should you try to go? Would Pikes Peak be a good launch site?
I think we've pushed this "anyone can grow up to be president" thing too far.
To compensate for drag in the atmosphere you need a muzzle exit velocity aroun 10-11 km/s. You'll still need a rocket on board to circularize your orbit less you come back down into the atmospher on the same parabola that you left. You can use this rocket to help you escape though and leave the the
:)
muzzle at a lower velocity. A 30 km launcher could accelerate cargo to 11 km/sec at 4000 gees, and could accelerate a rocket with people to 1.5 km/sec at 8 gees and save a lot of fuel for the rocket.
Of course, an even better solution is to build your mag lev accelerator into a loop like a particle accelerator... then you can accelerate at whatever rate you want
There are 10 types of people in this world, those who can count in binary and those who can't.
I wonder if anyone has considered the effect that a nuclear blast would have on this technology. Would the blast essentially reverse the polarity of these electro-magnetic fields and render them inoperable?
Magic Mountain, in Valencia, California. I believe it is the Superman ride. It launches a pretty massive set of roller coaster cars from 0 to 100mph at about 2 Gs. I'm not sure why the designers chose this method, but it is a great proof of concept.
To me, the best use of this kind of launcher would be to get an orbiter up to ramjet speeds, say 500 mph, then let it fly on ramjet power up to a tanker. I'd have the ship fully fueled with LOX, but with almost empty fuel tanks, so that it could be lighter and easier to get off the ground. Once fully fueled, use the ramjet to get to 100,000 ft and Mach 3 or so. From that altitude and speed, single-stage-to-orbit is remarkably easier than it is from the ground. You can use full-expansion engine bells to get good specific impulse, and going from Mach 3 to Mach 25 is significantly delta-V than 0 to Mach 25.
thad
I love Mondays. On a Monday, anything is possible.
Type it a hundred times, with no apostrophes:
His, hers, its.
Redistribution of this post is encouraged.
Metric units are not the end all be all of measurement...even in the sciences. Physics is littered with non standard(ie not SI) units of measurement. Things that come up off the top of my head, the entire Gaussian system where the speed of light is 1, and in nuclear physics the "barne" unit which measures nuclear cross-section size (a barne as units of area...)..though barne isnt a good examply becuase its still a power of 10 conversion.....a better example is the entire Gaussian system of units where 1 coulomb becomes 3E9 statcolumbs...or while I'm thining about it the unit of eV (electron Volt) which is 1.609 E-19 Joules
Why would the enlightened physicists not use the standard metric units.....becuase its a real pain in the arse to keep a track of all those blasted powers of 10 and other numerical factors when doing derivations and keeping track of information. Using Gaussian units cleans up maxwell's equations when you are deriving things by hand. The eV unit is a more natural unit to use when talking about particle energies...sure people could talk about an electron have 1.9E-19 Joules of energy...its much easier and quicker to say 1eV and to talk about eV's since eV's are a very natually base unit in a wide range of particle motion problems.
So English units still might be useful to some becuase it provide a quicker or more efficient way to encode certain information. Just the the eV is used, there might be an industry out there that thinks bushels just make sense when talking about dry volume....
Why is it that everything thing in an American grocery store is measured in English units except the soda bottles? Milk is in gallon, food are in pounds and ounces...but the Pepsi is in Liters.
-jef
Check out the homepage of Transrapid at http://www.transrapid.de/en/index.html
IMHO this is one more of those "Look what we've discovered"-news where this is already old news somewhere else...
We launch all these vertical craft using so much fuel, yet our planes do not. Planes do not use as much fuel and there are planes that are very large and heavy. So why not launch a plane holding a space shuttle, get the plane to the highest altitude it possibly can and then let loose the shuttle and launch it from there. Wouldn't this save a lot on fuel? Or is there really that much more to go from that "highest altitude" that it needs a large payload of fuel that the plane just wouldn't be able to carry?
Question everything.
I am not very familiar with maglev technology but as there are very strong and rapidly changing fields involved I would worry about the induction currents in any metal parts of the spacecraft. I am thinking of overheating due to large induction currents, damage to sensitive & expensive electronics, magnetization, erasing memory in chips, etc..
Some problems can probably be avoided with Faraday cages, and taking care that wires do not enclose large inductive areas. And maybe these issues are just not more serious than usual for a not so gentle event such as a rocket launch. Or maybe you can really confine the fields to the magnets/coils in the rail and in the launching component of the craft, with relatively very small stray fields?
Could anybody with background knowledge about space- or aircraft or large EM fields comment on this?
actually they pronouce it kuh-LOM-eter
;)
Few people here seem to understand the crucial issue. A couple do, but their posts haven't been modded up... here's another try.
You don't build a magrail to give your spacecraft orbital velocity. Of course that's silly, for the reasons given above. You use it to give you some small PART of your velocity. This is extremely beneficial.
The crucial insight is that each bit of fuel you use for some stage of the flight needs to be lifted be even more fuel in the previous stage. Think backwards from orbit and it will make sense.
Say you have a 100-kilo satellite you want to accelerate at a constant rate for some period of time. For the last second of your flight, you need to burn, say, 10 kilos of fuel. That means the second before that, you need enough fuel to accelerate 110 kilos, 100 Kg of spacecraft plus the 10 Kg of fuel you'll need in the next second. So you'll need 11 kilos of fuel for the second-to-last second of acceleration. The second before that, you need 12.1 kilos. and before that, about 15 kilos. If you know anything about exponentials, you can then imagine how much fuel you need for the FIRST few seconds of the flight.
(This is not actually quite how spacecraft usually work, but it illustrates the general point nicely)
Over 90% of the fuel you are carrying is used just to lift the rest of the fuel that is burned later on, and a huge fraction of it is burned in just the first few seconds. And of course each kilo of fuel you carry requires a larger spacecraft to hold it, which in turn weighs more, which in turn requires even more fuel. So, if you can use a 10km or 100km rail to get your first few seconds of acceleration, you save a huge amount of fuel. This means a smaller spacecraft, which in turn means even LESS fuel carried.
The power burned by the railgun/mass driver/maglev whatever may actually be more expensive in raw form than rocket fuel (i.e. kerosene, in Russian rockets, which is less expensive per joule than electricity. US rockets use liquid hydrogen, which costs a bundle because you have to use vast amounts of electricity to cool it.), but it doesn't exponentially increase in magnitude as you head down the rail, because it's transmitted through wires rather than carried as mass in the spacecraft. Every second, you only need the same amount of electricity you used the previous second.
The same is true of chemical-powered ram and shock cannons, where fuel filling a cylindrical pipe is combusted behind the accelerating spacecraft travelling through the pipe. (not recommended for human payloads).
Furthermore, if your spacecraft has wings, this may give you yet another benefit. The shuttle has wings, but launches straight up, meaning for the ascent they are just dead weight requiring a huge, exponentially-scaled mass of fuel to lift. But on an almost-horizontal launching system, the wings can provide lift, and thereby actually be useful on the ascent stage. This of course is made easier if the vehicle already has significant velocity before it even lights its engines.
This whole system may not be a panacea; I'm skeptical too. But it probably is worth looking into, because it may help and doesn't require any technologies that don't yet exist. (unlike skyhooks/beanstalks or other strangenesses)
I stole this sig from someone cleverer than me.
Yes, NASA is always chronically underfunded for it's intended missions, but fortunately they aren't the only ones working on it. The military invests a lot of money in R&D, including pretty far-out projects (thanks to DARPA), and there's a long, long list of technology transfers. So if the Navy develops this one for carriers, it won't be long before someone applies it to space.
---If you can't trust a nerd, who can you trust?
Nothing in the USA should be even remotely underfunded. According to recent reports over $100 billion dollars has been spent on the war against terrorism. According to the United Nations 1998 Human Development Report it would only take $9 billion to proivide clean water and sanitation for everyone on earth, $12 billion could provide reproductive health services for all women worldwide, $13 billion could give everyone on earth enough to eat, $6 billion could provide basic education for everyone who now lacks it, and you you would still have about $60 billion to play around with, which could easily fund Nasa as well as anything else.
And just suppose for a moment that instead of sharing that $100 billion with the rest of the world that you spent it only on needs that benefit the USA, not only could you fix up every money based problem in your country, but you would have enough spare money for all your scientific, medical, space research and development. If you just took half of that $100 billion and devoted it to aids or cancer research, think of the difference you would make.
Just think how that $100 billion would transform the USA into the most amazing country in the world, no hungry, no homeless, no slums, incredible advances in technology and science and so on. Not to sound like a trekkie, but it's this kind of money that would go toward transforming the USA into what it is now to a utopia like place that it is in starfleet times.
So what is more important, revenge or intellgent social advancment ? Don't complain about things like NASA being underfunded or having to walk home in a dark alley through a slummy criime ridden area, because your country does have the ability to do something about it, they just have different priorities
Btw, the only reason I am posting this anon is that I don't need my mailbox clogged up with e-mails by every gung-ho patriot with revenge and a chip on their shoulder to be spouting flag waving rhetoric at me. Personally, if you really want to wave your flag at me and impress me with what a great country you can be, you would use that $100 billion to improve your self socially.
No, you're just being dumb.
You're confused -- you want that extra launch velocity from the Earth's rotation for everything except polar orbits.
I hold it, that a little rebellion, now and then, is a good thing. -- Thomas Jefferson
Consider a gas-exhaust rocket. Say that the rocket has a mass of 1000 kg and the fuel has a total mass of 100 kg (don't know if it's realistic, just an example). The efficiency of this process (neglecting heat losses) is 100 / (1000 + 100) = 0.091 = 9.1%. Now, consider the earth/launcher system, with enormous mass compared to the spacecraft. The efficiency of this process is M2 / (M1 + M2) where M2 is a huge number compared to M1. This efficiency is close to 1, or 100%!
What this means is that the vast majority of the energy you put in ends up accelerating the craft. This is opposed to the gas-exhaust system where only 9% of the energy goes into the spacecraft -- the remainder is carried away in the exhaust kinetic energy.
If we ever hope to build large space stations, then cutting the cost of earth launch to $1,000 per pound won't cut it. On the other hand, this technology on the Moon, perhaps with solar cells providing the electrical power, would allow for very cheap transfer of lunar material, refined or not, to points earthward. That could be Earth orbit or L4 or L5.
So long and thanks for all the fish . . . !!!
At any scale, a simple pipe with pressurized
gas will be a cheaper way to accelerate something
than a string of coils _with friggin huge power
supplies and switches attached_.
A maglev system has to energize the coils
just ahead of the vehicle, and then shut them
off as the vehicle passes them, otherwise it
won't accelerate. The coils have to have large
fields to do useful work. To turn them on and
off fast (which is required as the vehicle
moves faster), requires large currents and
voltages, and thus power supplies and switches.
On the other hand, a 500 ton vehicle (typical
mass to carry significant crew and payload to
orbit) fit within a 10 meter pipe accelerated
at 80 m/s^2 requires a force of 40 MegaNewtons
(about the same as the Space Shuttle cranks out
at liftoff). This works out to 510 kiloPascals
pressure, or 74 psi in English units.
Over a distance of 32 km, which is the longest
path you can get on land (island of Hawaii,
and it will be curved slightly), you then
can get a max muzzle velocity of 2260 m/s,
which is 30% of orbital speed. Rockets take
you the rest of the way.
As a thought exercise for the reader, figure
out if you can match the model in the article
(60 mph) with a length of PVC pipe and a Sears
air compressor tank.
Daniel
Let's hope that the Navy research gets us a step closer to not burning all that Oxygen and Hydrogen to get to space...
Uh huh. And all the electrical power needed to launch a very large mass with maglev will come from where? Maybe from more efficient burning than shuttle engines, but we will still be burning something somewhere else on the planet to take it there. Solar and wind power just doesn't charge quick enough to gather it quick enough for these sorts of ventures. Yet.
There are still other problems to solve before we get to this step.
"Beware of he who would deny you access to information, for in his heart, he dreams himself your master."
Actually, the hydrogen in rocket fuel is produced directly from natural gas, not by electrolysis.
i saw one of these on star treck a while back.. nelix knew about them, he built modeles of them..for taking Ore from the planets surface maby? and some guy goues sueacidal and kills another guy or something, and they run out of air, and ect ect ect..yea..nelix and tuvok...
;)
My father is the John Cole quoted in the CNN article and it's his office that is managing the maglev (among a lot of much more interesting projects), so I am familiar with this particular project. No one at NASA want's to use maglev as the only method for putting anything into orbit, but rather as a launch assist for chemical rockets. You would be amazed at the weight savings just by accelerating a rocket to 500MPH before using onboard fuel. Also, another point missed by most is that while maglev has been around a while, one of the main problems has been power availablity. For an operational system, you will need 3-6 Megawatt's in 6 seconds. To solve that problem (they don't think they could get a large nuclear power plant just for this thing) they are thinking about using VERY large flywheels to slowly spin up and store the energy until launch. And funding is next to nill. The army was kind enough to donate a few model airplains for the test rig. I used to have some MPEG's of this, if I find the URL, I'll post them. For further perusing and some nice pics, try http://std.msfc.nasa.gov/ast/abstracts/0B_Cole.htm l
and http://std.msfc.nasa.gov/ast/index.html
John Cole Jr.
Well, not exactly. In a traditional launch, the initial thrust has to get the mass of the payload PLUS a whole LOT of fuel moving. But as the fuel burns, each pound (or ounce, or whatever unit you want) of fuel adds more actual acceleration than the last pound did, because it has the same thrust but less mass that it has to push. The efficiency of the energy spent can be calculated by taking the integral of how much thrust is produced as the mass it needs to push decreases. As the launch progresses, each ounce of fuel has more effect (in the goal of accelerating the rest of the fuel and the payload) than the previous one did.
In the mag-lev case, the mass of the object being launched starts out MUCH MUCH smaller than in a traditional case, and the entire object stays at that smaller mass. By the time the object has reached its target velocity, (I'm simplifying the math a little here) the total energy spent has been mass(final) times velocity squared, instead of the of integral of the mass(inital to final) times velocity squared (mass and time being our changing variables). It'd make more sense if I could figure a way to show mathematic equations in html ;), but if you've had some calculus it should make sense. Much less energy is actually used to get a given amount of mass to a given velocity.
Obviously, it still requires energy, but not nearly the amount of energy for a traditional launch. Likely (at this point in the development of the technology) the mag-lev launch would still require some fuel burn at the end, to get the vehicle from the post-mag-lev velocity to an orbital velocity, and to get it up to the right height, but a lot of energy would already have been saved.
In a nutshell, for emphasis: the vast majority of the energy required to launch something into orbit is used at the beginning of the launch, and mag-lev technology would be able to reduce the initial launch sequence's energy dramatically.
Any sufficiently simple magic can be passed off as mere advanced technology.
30,000 dollars? what the hell does that pay for? maybe one guy sits in an office doodling these things all day for 30,000 dollars a year... what other research could possibly be done for 30,000 dollars a year.
You don't build a magrail to give your spacecraft orbital velocity. Of course that's silly, for the reasons given above. You use it to give you some small PART of your velocity. This is extremely beneficial.
This turns out not to be the case.
First, calculate how fast a magnetic launcher can fire a craft.
Remember, the launcher needs to be pointed upwards. You can't just turn the craft at the end - G force limits would require a very large turning radius for this.
Assume a vertical launcher length of 1 km maximum.
Assume a maximum acceleration for delicate cargo (like people or delicate equipment) of 10 gravities (100 N). I'm ignoring gravity's contribution; accelerating upwards at 10 gravities, the cargo would feel 11 gravities of force.
This gives an energy transfer over the length of the gun of 1000m * 100 N = 1e5 J, corresponding to a velocity change of about 0.45 km/sec.
To get to low orbit - not geosynch or escape - you need a delta-V of about 8 km/sec. If you're burning liquid hydrogen, with a specific impulse in the 4000 N*s/kg range, you'll need a rocket that's ( 1 - exp(-8000/4000) ) = 86% fuel.
If you get 0.45 km/sec for free, you need a rocket that's ( 1 - exp(-7750/4000) ) = 85% fuel.
Magnetic launching gained you 1% of the rocket's mass for cargo. Not much.
If you can launch from an airless body like the moon, then you can build much longer launchers tangentially to the surface, which would be extremely useful for lifting payloads. However, I've yet to see any proposal for an earth-based launching scheme that would give a substantial benefit without an astronomical cost.
Building a magnetic accelerator several tens of kilometres long might work, but that would be insanely expensive, requiring huge traffic volumes to pay itself off. Building a laser-based launcher [basically a jet with a ground-based laser as the heat source] looks attractive at first due to long path length, but has strong limits on energy density (you don't want to ionize the atmosphere the beam travels through, or you'll get a reflective plasma scattering your light). A space elevator would be even more expensive than a magnetic launcher, would require advanced materials that we presently don't have, and could cause devastating amounts of damage if sabotaged.
In short, I'm doubtful of anything better than chemical rockets for launch of delicate cargo from Earth showing up any time soon. Space, of course, has considerably more interesting possibilities.
If you can build a thousand-gravity accelerator, then you might be able to send up sturdy cargo. However, that too would require very high volumes to be economically practical.
The technology thats going to allow you to build a personal rocket is here, but it's not this brain dead shit NASA is working on. Check it out.
:)
Don't expect to see this technology on CNN anytime soon. Heaven forbid the people might be given hope for a future unbounded. Lord knows we can't have that, who would pay the bills
2H2O? Unless I'm missing something shouldnt that be H2O - or water... (AFAIK they do burn O2 and H2 cos they're the stable forms os those elements, but they carry twice as much hydrogen as oxygen to balance out when they burn)
anyway, my point is that all the O2 and H2 has to come from somewhere - not sure how but the easiest way is to electrolyse water; which munches electricity like you wouldn't believe...
So, the electricity/energy is still used somewhere - the launch site isnt the biggest environmental impact in hardly any case.
$30,000 is big money to the folks over at railgun.org. I think they would love some of it :>)
What the previous poster meant was, that
1 molocule Hydrogen (H2) + 2 of Oxygen (O2) gives 2 of water (H2O).
If Slashdot accepted PRE, SUPER, and SUB tags, this would be a lot clearer.
You are right, it takes a lot of energy to make Hydrogen, but according to Web Elements the normal approch to making Hydrogen is stream + ( carbon or methene), electrolsys of sulphuric acid (SO4+ goes through a complex system, and releases Oxygen, but is far more conductive that water) is too expensive, but it might be different if you want an oxygen supply as well. The reactions above produce carbon dioxide, so unless its aneroibic methene, Hydrogen rockets will still produce excess CO2.
Anyway, for space launchs, the rocket must either be self powered, or doing atleast the escape velocity when it leaves the end of the launch-rails, which, for the Earth, is 11km/sec, well above the speed of sound, so unless you lauch from the top of a mountain, there will be too much atmospheric drag for non-self powered lauches.
To determine the escape velocity use this formulae
sqrt(2 * Gc * M / r) (from Astronomy 120)
Where Gc is 6.6725e-11 kg-1m-1s-4
M is planent's mass 5.9 72e24 kg for Earth
r is distance of launch from planet's centre (6.378e6 m)
It has become appallingly obvious that our technology has exceeded our humanity. --- Albert Einstein
Dad emailed me his video of the Nasa maglev mentioned in the CNN article. It's in mpg format (6.35MB).
I've posted it here.
John Cole Jr.
I believe the high strength-to-mass ratio for carbon nanotubes is part of what inspired that fifty year timeframe NASA has. Have to figure out how to mass-produce the stuff first though.
If I remember correctly, if it was counter-weighted right, most breaks would send the cable flying off into space instead of down to the surface. Something like that.
:P
simply calculating back from orbit means you can never have enough fuel to lift the fuel you just added, ad infinitum
You have to factor in the fact that your craft gets lighter as you ascend - because it is shedding fuel when it burns it.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Definitely doesn't need to be vertical - you're out of half the atmosphere in 7 miles, out of over 99% of the atmosphere by 50 miles high, and by that point the velocity you need to get to orbit needs to be horizontal, not vertical; you still need some vertical thrust to counteract gravity of course, the main point is there's an optimal thrust/weight ratio beyond the atmosphere that is also associated with a specific curved trajectory, far from vertical...
Energy: time to change the picture.
1. it does NOT have to be vertical(watch what the shuttle does soon after launch), so the acceleration can be done over longer distance, so less G's. think rail's in hundreds of miles. Expensive, yes, but less than 100 million per launch of shuttle.
I've done the calculations. Have you?
At 0.5 km/sec, and a maximum radial acceleration of (say) 10 gravities, your minimum turning radius is 2.5km - bigger than the 1km gun!
If you're building a horizontal gun and making the end turn up, turning radius gets _worse_, because of the higher muzzle velocity. It goes up as the _square_ of the velocity! You need a tower high enough that you might as well make the whole gun a tower.
Mount Everest is 4.4 km high. If you carve a giant channel in it, so that your gun gracefully curves, you get a maximum muzzle velocity of around 0.66 km/sec. Still very, very low.
If you just run a straight gun up the side of a mountain the size of Mt. Everest, you get a straight gun around 6 km long. At 10 gravities maximum acceleration (as per previous post), this gives you 6e5 J, or a velocity of 0.77 km/sec.
Still not enough to make a worthwhile difference.
Bear in mind also that tilting the gun at an angle, like you would going up the side of a mountain, gives you much more atmosphere to go through on the way up. If you try to turn the craft in the atmosphere, you're still forced to turn slowly, and your acceleration limit will be much lower than for a turning gun barrel, making the turning radius much larger (turning radius is inversely proportional to radial force).
2. even if it did, you could just build it up the side of a tall mountain, and have it curve gently up, which is kinda the most likly solution anyway, as it put you higher in the air, so less air resistance, closer to orbit, that type of thing.
Air resistance effects are negligable if your rocket's cross-sectional mass is much greater than the cross-sectional mass of the atmosphere it'll be plowing through (15 tonnes per square metre), or if it does most of its acceleration outside most of the atmosphere.
For a conventional heavy-payload rocket, both of these conditions are true, and atmosphere resistance doesn't matter.
Air resistance effects are negligable if your rocket's cross-sectional mass is much greater than the cross-sectional mass of the atmosphere it'll be plowing through (15 tonnes per square metre), or if it does most of its acceleration outside most of the atmosphere.
Correction: This is 10 tonnes per square metre if you're going straight up (about 15 pounds per square inch).
You could superheat some water under pressure. When you let the pressure off, the water explodes into steam. This ultra-high pressure steam could be directed down a long barrel to propel a rocket forward. You could reach fairly high speeds with this method at a much lower cost than superconducting magnets.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Since going from zero to 11 miles/second is really hard on material objects, especially science instruments, its far more likely that the mag-lev will be used much the same way that Navy catapults are. As launch-assist devices. I see them as replacing, for example, the Solid Rocket Boosters the shuttle uses. The launch vehicle still has rockets, but requires a lot less mass be allocated to fuel. Because of the rather low G-tolerances of the human body, they won't be used for manned space-flight. They will be used for hurling more rugged sats into orbit.
Gee, you'd think this would be all common knowledge, after all, it isnt exactly rocket science (oh wait....)
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One of the short stories in "The Green Hills of Earth", I think, though I can't remember the specific title at the moment. In one scene the pilot is tensed up waiting to see whether the engine of his rocket will fire upon being launched, or if he'll have to abort and glide it to a landing.
A. Safer - all equipment on ground easy to maintain and in case of a failed launch or problem the rail would still result in a partial launch - meaning the pilot could presumably guide the plane/wahtever to a landing.
Maybe, maybe not. What if it tosses it fast enough to come off the rail, but not fast enough to maintain (gliding) flight? No safe landing!
- No need to carry volatile chemicals
Sorry, no. Maglev launched vehicles are going to have to carry significant amounts of fuel to boost themselves into orbit. Otherwise they'll pay an incredible penalty in heat sheilding to overcome the atmospheric heating at launch. (And it will be in different places mostly than that required for reentry, so no saving there.)
B. Cheaper since, once agian, everything is on the ground - no need for throwaway boosters, etc Indeed once you pay for the construction all that is left is electricity and maintence.
Maybe, maybe not. You have to get the launch rate up high enough to amortize the cost.
Dude, the point is you only have to launch the capsule. Using a rail gun means you can leave the rocket part on the ground.
That is -way- cheaper.
Plus you can generate and store electricity any number of ways, all of which are cheaper and easier than high test rocket fuel and liquid oxygen.
I tried google search on core oscillations, (and same with Eisenberg and same with Pronellis), and on Eisenberg Pronellis, to no avail ...
In his Cosmographicum Mysterium, by a study of harmonic division of space (platonic solids), Kepler, in the 1600's +/-, predicted a missing planet between Mars and Jupiter, i.e. at the asteriod belt. I am interested in more.
Any links pointing to the work of Eisenberg-Pronellis appreciated!
Could this be combined with the giant 'ski jump' they used to lauch the spacships in 'When Worlds Collide'? Why can't they use a ski jump now for regular shuttle launches? Its good enough for the British Navy.
MrCreosote Meow!Thump!Meow!Thump!Meow!Thump! "You're right! There isn't enough room to swing a cat in here!"
First of all, when you are talking about a material's ability to support its own weight, the property that is important is not tensile strength, but rather specific tensile strength (the amount of tensile strength per unit mass).
And you are correct, when I did the thesis 10 years ago, no known material was strong enough. The best specific tensile strength belonged to Kevlar/Spectra-type polymers, and they fell short by a factor of about 500. Nowadays, carbon nanotubes might fit the bill.
You could conceiveably built a tower (many km tall) at the earth's north or south pole, attach one end of the cable to the top of the tower, and attach the other end to the surface of the moon. The attachment to the top of the tower would have to be a pivot, so the earth can rotate under the cable. The tension in the cable would be enormous, and I did not study what effect that constant tension at one pole would have on the earth's rotation. I imagine it might induce nutation over a period of years. The tension might also affect the moon's orbit non-negligibly.
That that is is that that that that is not is not.
You create a small track to launch raw materials. Hopefully they can withstand the gs. Then once the tech is proven you create larger and larger rails allowing you to launch larger objects with smaller accelerations. Eventually it could be possible to launch human payloads safely. Once the vehicle is launched you have an orbital shuttle that docks with the payload and brings it safely to a station or orbital factory. These things will take time to build, but at least we're starting to get on the right track with this article. There's no way we'll ever be able to build our space stations or factories without maglev launches. The materials to build these things are simply too heavy to launch affordably any other way, and we're too stupid to learn how to mine them in space. (Oh and since electricity can come directly from the sun it is in abundance and hella cheap. Don't make me smoke you out and show you the light).
Hopefully nuclear fusion will improve within the next couple decades to help us reach the asteroids or mars or at least the moon efficiently and safely.