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Startram - maglev train to low earth orbit

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March 9, 2012

The Startram orbital launch system would transport passengers and cargo into space in a ma...

The Startram orbital launch system would transport passengers and cargo into space in a magnetic levitation (maglev) train

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Getting into space is one of the harder tasks to be taken on by humanity. The present cost of inserting a kilogram (2.2 lb) of cargo by rocket into Low Earth Orbit (LEO) is about US$10,000. A manned launch to LEO costs about $100,000 per kilogram of passenger. But who says we have to reach orbit by means of rocket propulsion alone? Instead, imagine sitting back in a comfortable magnetic levitation (maglev) train and taking a train ride into orbit.

All right, its not quite that simple or comfortable - but it should be possible using only existing technology.

Dr George Maise invented the Startram orbital launch system along with Dr James Powell, who is one of the inventors of superconducting maglev - for which he won the 2002 Franklin Medal in engineering. Startram is in essence a superconducting maglev launch system.

A spacecraft emerging from the Startram magnetically levitated launch system
A spacecraft emerging from the Startram magnetically levitated launch system

The system would see a spacecraft magnetically levitated to avoid friction, while the same magnetic system is used to accelerate the spacecraft to orbital velocities - just under 9 km/sec (5.6 miles/s). Maglev passenger trains have carried passengers at nearly 600 kilometers per hour (373 mph) - spacecraft have to be some 50 times faster, but the physics and much of the engineering is the same.

The scope of the project is challenging. A launch system design for routine passenger flight into LEO should have rather low acceleration - perhaps about 3 g's maximum, which then requires 5 minutes of acceleration to reach LEO transfer velocities. In that period, the spacecraft will have traveled 1,000 miles (1,609 km). The maglev track must be 1,000 miles in length - similar in size to maglev train tracks being considered for cross-country transportation.

Like a train, the Startram track can follow the surface of the Earth for most of this length. Side forces associated with the curvature of the surface can be accommodated by the design, but not the drag and sonic shock waves of a craft traveling at hypersonic velocity at sea level - the spacecraft and launching track would be torn to shreds.

To avoid this, the Startram track must be contained inside a vacuum tube with vents to allow air compressed in front of the spacecraft to escape the tube. A vacuum equivalent to atmospheric conditions at an altitude of 75 km (about 0.01 Torr) should suffice for the efficient operation of the Startram launch system. Rapid pumping to achieve this pressure will be provided by a magnetohydrodynamic vacuum pump.

If the entire Startram tube is at sea level, on exiting the tube the spacecraft will suddenly be subjected to several hundred g's due to atmospheric drag - rather like hitting a brick wall. To reduce this effect to a tolerable acceleration, the end of the Startram vacuum tube must be elevated to an altitude of about 20 km (12 miles). At this height, the initial deceleration from atmospheric drag will be less than 3 g's, and will rapidly decrease as the spacecraft reaches higher altitudes.

View of the magnetically levitated Startram launching tube rising toward the skies
View of the magnetically levitated Startram launching tube rising toward the skies

This new requirement begs the question - how do we hold up the exit end of the Startram vacuum tube? Well, the tube already contains superconducting cable and rings. Powell and Maise realized that the tube could be magnetically levitated to this altitude. If we arrange that there is a superconducting cable on the ground carrying 200 million amperes, and a superconducting cable in the launch tube carrying 20 million amperes, at an altitude of 20 km there will be a levitating force of about 4 tons per meter of cable length - more than enough to levitate the launch tube.

The Startram launch tube is securely tethered to ground
The Startram launch tube is securely tethered to ground

The vacuum tube would be held down against excess levitation force by high strength tethers. Dyneema (UHMWPE) is more than strong enough for this purpose. Redundant design would make a failure of the levitation system most unlikely.

The Startram launch system contains other technological wonders, such as a plasma window on the exit of the vacuum tube to prevent the inrush of the relatively dense air at that altitude from ruining the vacuum within the tube. However, all the required technology exists and is understood. The only engineering effort involved here is in increasing the scale.

Sandia National Laboratories has carried out a '"murder-squad" investigation of the Startram concept, whose purpose is to find any flaw in a proposed project. They gave Startram a clean bill of health. Estimates suggest that building a passenger-capable Startram would require 20 years and a construction budget (ignoring inflation and overoptimism) of about $60 billion.

Why take on such an enormous project? Simple - $50 per kilogram amortized launch costs. The total worldwide cost of developing and using rocket-based space travel is more than $500 billion. The Space Shuttle program cost about $170 billion. The International Space Station has cost about $150 billion to date. As yet, we are making very little commercial use of near-Earth space beyond deployment of communication and imaging satellites. Reducing the LEO insertion costs a hundredfold should finally start our commercial exploitation of the special resources of space. Not to mention making orbital hotels a travel goal for middle-class tourists!

Source: Startram

About the Author
Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer.   All articles by Brian Dodson
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54 Comments

Just the sort of project Kick Starter was invented for.

Russ Pinney
9th March, 2012 @ 03:24 am PST

When's the movie coming out?

3razer
9th March, 2012 @ 05:19 am PST

A "Space Elevator" still seems a lot more feasible.

Chuck Anziulewicz
9th March, 2012 @ 07:10 am PST

Wow....way to rip off the Jules Verne Gun Company.

VoiceofReason
9th March, 2012 @ 07:26 am PST

I'm skeptical of space elevators, because they're stationary and eventually a satellite is going to ram the thing. Not to mention it's a delectable target for terrorists. Before I thought about the maglev approach, which would cost many billions, I'd consider building a large, very fast jet (reusable of course) as the first stage to get the second stage up to speed, and then release the spacecraft. I guess that's similar to what space-x is doing, but they just need a much bigger and faster initial stage. Hopefully scram jets will be developed before too long.

Bob Tackett
9th March, 2012 @ 08:33 am PST

While fanciful, a project like this will be impossible to execute. There are too many stumbling blocks for something that requires 1,000 miles of surface tracks and an ungodly amount of electrical current.

What might be more feasible would be a "hybrid" system that has a few miles of track sloping up a mountain to 5,000 MSL with a conventional rocket taking over at release. Such a system might accelerate a rocket to several hundred MPH instead of escape velocity. That would reduce the cost of the entire system to something reasonable. It would also fit on an existing military reservation.

I think the actual solution to exorbitant launch costs is what SpaceX is constructing: A 100% reusable space launch system.

coryatjohn
9th March, 2012 @ 08:46 am PST

There are too many reasons why this specific concept wouldn't work. The very notion of building a 12 mile high structure to eject a small spacecraft is not feasible engineering.

For comparison, the Burj Khalifa is 829m tall (0.51 of a mile), and the biggest force it has to withstand is side-loading from the wind, which can be even higher than it's own footprint weight on the ground. Magnetic levitation does not solve this problem, and 12 miles is only 63,000ft, well short of the 62 mile / 327,000ft Karmann line.

The space elevator concept might be better, where if you built it high enough, eventually you can have the structure in centrifugal tension due to the earth's rotation, but the forces resulting from the winds would dictate an impossibly high tensile strength requirement.

Bob Tackett has the right idea - the mother ship with space-plane concept like Space Ship 1 white knight 2, but on a larger scale. This is the most cost-effective and most efficient approach.

PeetEngineer
9th March, 2012 @ 10:30 am PST

While it might be possible to build, the cost estimate is a joke. California's paying 65-100 billion for a few hundred miles of high speed rail - just normal steel rails. There's no way they'll get 1000 miles of superconducting rail in a vacuum sealed tube for 60 billion.

seanw
9th March, 2012 @ 11:18 am PST

Even starting at a height of the highest mountains doesn't get us half way to 12 miles up. But since non-living things could withstand more Gs, why not a lower altitude, faster version of this for raw materials ane equipment? People can rendezvous later using the mothership approach. Or add some propolsion to counteract all the Gs of exiting the tube at a lower altitude. This might not be feasibile, but you could go faster (at a lower altitude) but gradually introduce the atmoshpere after it exists, by extending the tube and letting in controlled amounts of air, until it matches outside atmosphere. And instead of 1000 miles in a line, why not do it in a repeating circle, electronically controlling the amount of magnetism until launch speed is reached, and then switch the track (like a train) to the escape track. Bottom line - I could build my version of this for $20 billion! :-)

skullzen
9th March, 2012 @ 11:32 am PST

A 1000 mile long, 12 mile high track doesn't seem feasible, as others commenters have noted.

However, if the payload was limited to cargo, much higher g's could be used. Then, the runway could be significantly shorter. The runway could be further shortened with coryatjohn's "hybrid" system. Now, we may have a system that is (1) feasible not only in terms of construction but also for maintenance and security and (2) commercially competitive. Perhaps, even new possibilities for ground-to-ground cargo transportation.

Another Anonymous
9th March, 2012 @ 11:36 am PST

A science-fiction novel of many years back proposed the identical design, so it's not a new concept. It may be more practical and less expensive if one considers the design from the book and today's technological advances. I can't recall the book, so much the worse, but the launch structure was cut into a mountain.

We have huge tunnel boring machines that could be considered to dig from the launch opening downward until the thousand mile point is reached. Combining some of the above ground aspects of this design with some in-mountain aspects of the design from the book may make things more practical.

fred_dot_u
9th March, 2012 @ 11:39 am PST

I prefer an orbital tower it would cost less to operate and a hiccup in you power supply doesn't being it crashing down.

anybody capable of calculating Spaceship 2s velocity it it used a Concord as the mothership.

Slowburn
9th March, 2012 @ 12:25 pm PST

See The Bridge To Space, by Mike Combs.

http://writings.mike-combs.com/bridge.htm

Ross Presser
9th March, 2012 @ 12:37 pm PST

"The only engineering effort involved here is in increasing the scale." That's exactly what I said about my Estes rockets making it to orbit when I was eight.

The historical 10x cost for human space travel is due to the safety factors introduced in the system that, among other things, includes tracking material sources to their raw component origins (e.g., paperwork showing the exact mine in the earth the aluminum came from to build the habitation modules of the ISS). That's where the expensive hammers and toilet seats have come from, safety paperwork. A great deal of effort goes into making sure chosen materials for orbital equipment does not endanger lives, equipment or mission.

The high cost/kg of the Shuttle was not due to the cost to build as much as due to the size of the ground crew required to maintain and refurbish the shuttles for each flight, combined with the very low rate of launch (i.e., not a lot of kg were actually launched by the shuttle compared to the projected schedule of 1 launch every two weeks). For any flight system, increasing flight frequency only allows costs to asymptotically approach the cost of employing the personnel on the ground and those flying--assuming valuable resources are not also be retrieved from space.

(And, of course, they are bringing back valuable resources, but most are in intangible forms such as research that will not soon offset the costs of the launch system. I support any argument that the Apollo/Shuttle/ISS, etc, missions have more than paid for themselves in science and spin-off technology.)

A low-cost system for manned spaceflight will require a high frequency of flights and a relatively small ground crew for maintenance and launch. The problem is less about the technology to get to orbit and more about the logistics savings of turnaround and maintenance that the technology provides. I like the concept but until Startram makes estimates on the size of the ground crew, re-use savings, refurbishments and maintenance, then this is a lot of really cool hand-waving.

kogun
9th March, 2012 @ 12:45 pm PST

You guys commenting are ignoring the Sandia National Laboratory murder-squad detail. Unless you have comparable engineering chops, you can't say it isn't feasible. The mere fact that all the technology exists is pretty much all that's needed to pronounce it feasible.

The issue here is that people can imagine a rocket, but not a 1600 km long magnetically levitated track. But make the effort - what do you get at the end of this project, even if it runs over budget by 1000%? A railroad track into the sky. That should be all caps, but i don't want to be irritating.

It will never wear out, it just needs to be maintained. You could put millions, billions of tons into orbit. Billions and billions of tons. You could build a freakin' city up there. You would definitely make your money back, no question.

Kim Holder
9th March, 2012 @ 01:05 pm PST

This is all ridiculous. This is just as far off but seems infinitely more feasible>> http://www.reactionengines.co.uk/

Chris Cranmer
9th March, 2012 @ 01:09 pm PST

The only place you can or would build this is in fantasy land. One worked advanced heavy industrial construction on military mega-projects... some of what we did was, at first, beyond our ability to do and each day we set precedence at scales that would defy imagination. Even if we had the ability and material to waste building this 1000 mile long, 12 mile high, 200 million ampere space train; it would be obsolete far before the 20 years it would take to complete. Why? All I will say is that we have highly classified technology that exists now which already makes this nothing more than Jules Verne Moon Gun and just as amusing to those who know better.

Sysop
9th March, 2012 @ 01:20 pm PST

The reason this thing has to be 12 miles tall is that the end of the tube has to be outside of the atmosphere (or at least, practically so). Otherwise hitting the air at mach 15 at the end of the cannon is like hitting a brick wall.

Though, if you can hold this immense structure up 12 miles into the air using magnetic levitation, why not simply levitate and accelerate the spacecraft that way in the first place, and eliminate the cannon?

Jon A.
9th March, 2012 @ 01:25 pm PST

I need to follow up with a correction as Startram does provide some maintenance numbers. "Personnel @ 50 man days @ $500 per day". That's 400 man hours (per launch. The require 10 launches per day for amort. numbers.) At $500/man-day, or $62.50/man-hr that averages to personnel cost of ~$130k/yr. To work the average salary, account for insurance and other non-salary benefits and they estimate the average pay to be about $70k per year per worker. These are not unreasonable numbers for some industries, but even distributing costs into a pyramid of blue-collar, white-collar services, white-collar technical, and administration this is not going to account for very many people. If they want to impress me, they need details on how the launch facility will operate and accommodate 400,000 passengers per year. The estimates are so high level (a single line item for personnel, shown above!) and yet critical to overall costs to orbit that it shows that the focus is really on the cool technology and much less so on making space flight more affordable.

kogun
9th March, 2012 @ 01:32 pm PST

Call it the "Galaxy Express" and they'll have Japan behind it. ;)

Using helium filled balloons to hold it up would be far simpler and extremely less energy intensive than magnetically levitating the tube. Overbuilding the lift capacity would make losing a few balloons once in a while basically a normal part of operation. Just run a new one up the tube with an automated replacement system.

Cut the power to the levitation system and the whole thing comes smashing down in seconds. Wouldn't matter how segmented or redundant the levitation system is, there would be a way to take it all out at once.

With balloon support some terrorists would have to come up with a way to physically get at the majority of them to rupture them. Not an easy task up so high.

With any support system, the weakest point would be where the bottom end is at ground level. Pop off a bomb there and the whole tube is blowin' in the wind. Attack there and all or most of the ground tethers and that would be quite a mess.

Yeah, these things are *possible* but not very practical due to the ground space, the amount of energy and the vulnerability to idiots who can't get along with anyone else and express themselves through explosives.

Gregg Eshelman
9th March, 2012 @ 02:49 pm PST

4 tons of lift per meter of cable at 12 miles. Can you imagine the intensity of the magnetic field anywhere near this construct? I'm not a paranoid ignoramus, but I'm not sure I'd want to be anywhere near that, never mind riding a train just underneath one of those cables. Making sure all equipment onboard is properly shielded against the field would also be a challenge. We're talking many orders of magnitude stronger than the magnetic field around an MRI machine, and people have been killed by flying objects attracted by those.

Gadgeteer
9th March, 2012 @ 03:47 pm PST

Internally similar to a maglev train, comparable to linear AC motor, plasma turbine is to be cheaper and work better because the track for plasma turbine will be the Earth's atmosphere.

rbrtwjohnson
9th March, 2012 @ 04:18 pm PST

The sci-fi book someone was wondering about above is Robert A Heinlein's "The Moon is a Harsh Mistress" where, more or less, the moon colony fights for independence by using a maglev system to lob rocks at earth as bombs against strategic targets. At least that's what I remember from reading it more than 30 years ago.... :)

Pretty cool, and was written way back in the 1960's!

Limos
9th March, 2012 @ 06:28 pm PST

I read at the time, 32 people who expressed their opinion, and some were good, and some... Not so good. Outside the ability to produce the amount of power required for something like this, all of the super-conductors, and just the man-labor to build this thing........ Damn, it would be KICK-A$$! Provided something major didn't happen, and everything went just right, but does that ever happen? Still though, either concept this or the space elevator would be cool!

On a side note, you readers out there ever notice this.. Whenever an article like this comes along on this site to be very specific, the comments sky-rocket! It's good to see the constructive criticism. Such a shame these things are that expensive...

Adam Ackels
9th March, 2012 @ 09:00 pm PST

re; kogun

The space shuttle was badly designed. If it had been designed to require no more maintenance than a Boeing 747 between flight even if it required twice as much fuel to get to orbit it would have saved billions. (milliard)

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re; Sysop

Jules Verne Almost certainly knew better but the crude black powder rockets of the time sounded even more ludicrous.

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re; Jon A. The aerostat launch system provides an altitude advantage better than a high mountain and can provide an optimal launch point but does not provide any acceleration unless it is really big and has a linear accelerator of its own. Incidentally lofting a rocket with a balloon to get additional altitude was pioneered in 1949. http://en.wikipedia.org/wiki/Rockoon

In Orion Shall Rise one of the original purposes of the aerostat Skyholm was as a launch point for rockets.

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re; Limos

Launching from the moon the atmosphere is a non-issue even at the top of mount Everest the atmosphere might as well be glue for an hyper-sonic craft.

Slowburn
9th March, 2012 @ 09:23 pm PST

We should start now. Places to invest the money we send to China from Wal-Mart that they send back here are needed. Investment guaranteed to pay off (a 200:1 cost reduction brings personal travel down to Concorde ticket prices and that's without the development of mass demand at both ends - and into the round-the-world FedEx range for freight). Some jobs would be created too to build something 1000 miles long, and some material production infrastructure for very versatile materials would be created.

Space is where they keep the Energy, the Matter, the Room, and the ability to toss stuff away and forget about it. AND having all the breeding pairs in one cage is not wise in the long run. Finally this is a rare example of the kind of thing that the US could do now, and POSSIBLY the other continental states in a generation; it could bring a new edge and stability to our situation without actually doing anything TO anyone else.

john werneken
9th March, 2012 @ 10:19 pm PST

We already have electrogravitic ships operating, so just make much larger ones for space at Zero point.

Paul Perkins
10th March, 2012 @ 12:20 am PST

China is looking at Maglev Trains running in a tunnel vacum. The idea of using this for space could achieve thousands of miles perhour through tunnels underground leading to a mountain that would assist projection. The fuel saving for cost of initial launch would be enourmous? The secondary boost system coming from hydrogen would be the tricky part this attached to the primary maglev would be high risk that would need considerable investment to achieve safety?

Basicaly Run underground to high speed / Release at maximum altitude / Use Booster Rockets to take into orbit (Easy )

The Straw Man Principle

Facebook User
10th March, 2012 @ 12:46 am PST

This is a fanciful idea but orders of magnitude more likely than a space elevator.....

If the tube can be mag-lev'ed, it is an interesting concept, and to save power between launches, just winch in the tube for stowing..... (at ground level)

Space elevators have a big flaw....

People forget that the counterweight in space may have its balance point at the geostationary point, but the mass will be so large that keeping it all stationary and in a straight line back to the earth anchor point is likely to be impossible.... its not Just a matter of the weight At geostationary orbit.... it is the bulk of the mass must be a long way beyond that, in a slower orbit than the earth rotational speed.

But without the dreamers of science where would we be....

I love to dream ,often reality hits me between the eyes...

MD
10th March, 2012 @ 06:17 am PST

seanw, I'm afraid your idea of a circular repeating track wouldn't work; even if the radius is a quite large 100 km (628km=392 miles of track), when the vehicle reaches 9 km/s, it will go around the entire track in only 70 seconds, and the centrifugal force at that speed is 810 m/s^2 (83 Gs), well over 20 times the maximum for human passengers!

kogun's idea of helium baloons sounds nice, except their size would be mind-blowing. Google tells me that helium lifts only one gram per litre, and that's at sea level. Even if the track weight could somehow be reduced to 2 tons per metre, so at sea level you'd need a continuous balloon (no gaps) with a cross section of over 2000 square metres, which (if circular) is least 51 metres in diameter at sea level -- and I expect the size would have to increase dramatically as the altitude increases. I suspect that such enormous balloons would cause unacceptable wind loading.

I have never heard of any wire carrying 200 million amps (and at what voltage?) but if critical scientists say it's possible, I guess it's possible. But if this electromagnet can lift a track that is 12 miles away, what effect would it have on metal objects and electronics that are much closer?

As for the idea that the track will come "crashing down" in case of power loss, I'm sure they've thought of that. The first idea that comes to my mind is a series of parachutes, plus a web of bungee cords to catch the track when it reaches ground level. The cables that normally keep the track stationary can be designed to passively (without power) guide the descent.

I wonder if this project could be combined with a point-to-point passenger train, with some of the cars going to space and some of the cars going from one city to another. Enabling more than half of the track to be used for two different purposes might make it a "safer" investment.

Finally, I wonder if this thing could be used to reach higher orbits, especially for unmanned trains using higher acceleration. If so, this train could be used to build a space elevator by cheaply sending rolls of carbon nanotubes into space. If the maglev itself can't provide a high enough orbit, either rockets or an ion drive could boost the material to geosynchronous orbit.

David Piepgrass
10th March, 2012 @ 11:04 am PST

This will be the best roller coaster ever!!!

Sfn Corp
10th March, 2012 @ 03:09 pm PST

re; MD

The counterweight of an orbital tower is forced to move much faster than orbital velocity for the altitude and therefore it is pulling the top of the tower out with a great deal of force.

Slowburn
10th March, 2012 @ 06:30 pm PST

interesting concept, however i feel the best way into space would be through teleportation, which is becoming more of a reality every other article a read about it.

Gideon Oladunjoye
10th March, 2012 @ 11:59 pm PST

StarTram fits the big picture, see e.g.,

The evolution of transport (PDF). The Industrial Physicist 7(2): 20-24, 2001 http://www.aip.org/tip/INPHFA/vol-7/iss-2/p20.pdf

Jesse Ausubel
11th March, 2012 @ 10:02 am PDT

"Powell and Maise realized that the tube could be magnetically levitated to this altitude. If we arrange that there is a superconducting cable on the ground carrying 200 million amperes, and a superconducting cable in the launch tube carrying 20 million amperes, at an altitude of 20 km there will be a levitating force of about 4 tons per meter of cable length - more than enough to levitate the launch tube..."

So why don't we skip the tube and train and just have a "launch pad" with "200 million amperes" built into the pad and "20 million amperes" built into a capsule of some kind and shot it right up into orbit?

Justa__Free__Thinker
11th March, 2012 @ 02:50 pm PDT

A hybrid system running up the side of the mountain seems more cost effective, safe, and require less materials. In order to deal with the thick air at approx 2 miles up (some extension made off of a mountain) it would be wise to consider creating a plasma in front of the vessel to reduce drag. Both the vessel and tube can generate the necessary energy beams for plasma generation to help reduce weight/fuel requirements of the craft .

http://www.bibliotecapleyades.net/ciencia/secret_projects2/project318.htm

Gary Richardson
11th March, 2012 @ 03:37 pm PDT

So the project would take 20 years,after which NEW technology would be available and the space tram would be obsolete. WHAT a JOKE. This whole concept sounds like something a child would dream up. I dare say they've considered every possible scenario but making a structure that karge earthquake and wind proof is another thing.All it would take is one little hiccup and the whole thing would be history. It will NEVER happen.

paulgo
11th March, 2012 @ 06:29 pm PDT

I'm not sure if I understand this correctly. How exactly would we levitate a 1000 long tube, that probably weighs millions of tones, 20 miles at an angle? Against a superconducting cable in the ground? Is that even possible with this much weight and distance?

Ok, if it is possible to lift that much weight with a superconductor why not skip the complicated middle man altogether and build the ship out of superconducting material, maybe a big disk, same with the platform and shoot the disk up into space 20 miles? Am I the one missing something here, or is it the article/concept that is in the miss?

AnOld BlackMarble
12th March, 2012 @ 01:01 am PDT

The Achilles heel is, what if the maglev power ever fails. Then you have a 60 billion space tube crashing into the ground, or more likely some part of it kinks and ruptures and falls to pieces. If it happened while someone were accelerating in the tube, the ship would be turned into paste while the tube explodes into smithereens! Lighter-than-air lift is more realistic, at least it doesn't rely on power not failing.

I would say the most realistic thing is to orient the tube straight up and through the centre of a 12 mile high tower. But anybody who has been in a super high skyscraper knows that it sways quite a bit up there, the resulting motion would cause a high speed collision of the ship inside the tube with totally catastrophic results. If you cannot build a 1 km high tower rigid enough for the job, what makes anybody think a 12 mile long tube could be made rigid enough?

In fact I can confidently say, 12 miles of tethering cables will have so much elasticity to them that the end of the tube cannot be held rigidly enough to hold the pathway straight enough to prevent a tube crash.

Grunchy
12th March, 2012 @ 08:57 am PDT

For all those who wanna skip the whole construction in favour of a superconducting magnetic levitator. Space doesn't begin at 20 km. Stratosphere does. The aim of the construction is not to lift the vehicle up to 20 km (a simple jet plane can achieve that), but up to 300-400 km, or more. For that you need to accelerate the vehicle to escape velocity.

senorga
12th March, 2012 @ 03:40 pm PDT

Doing this on Earth and having it accelerate slowly enough for human cargo does not seem the best application of this approach. Having a scaled down, faster accelerating, version might be usable. Planets (and other stuff) smaller (or rather fewer Gs) then earth could really benefit from something like this though. Imagine having it on the moon to hurl resources into orbit for construction work there...

Jeroen De Dauw
13th March, 2012 @ 05:01 pm PDT

...another wild-azz idea, but nonetheless interesting.

For me, we need more details about how the tube would be secured on either end. Essentially, the track structure would be a 100-mile straw from earth into space. What kind of vacuum-effect force would we expect at ground (or 12-mile high) level? Just like a space elevator, what keeping earth's atmosphere from being constantly sucked out into space?

Smoov Mocha Nut
14th March, 2012 @ 12:01 pm PDT

Excuse me, none here seems to question the whole superconducting business, which is I believe the principal showstopper.

Even assuming a very optimistic engineering current density of 1000 A/mm2 with state-of-the-art Nb3Sn cables (which, by the way, will be proven to work reliably in large-scale applications only 10-15 years from now in ITER), the conductor should be spread over a large cross-sectional area of about 100 m2 in order to keep the peak field reasonably below quench limit, say a factor 2 below 15 T at 4.2 K. A large steel structure would be necessary to keep the cables apart and this, together with the cryogenic system plus the rest of the launching structure, is likely to get very close to the minimum 40 ton/m lift available.

The main problem however lies in the fact that today superconducting magnets do quench quite a lot, unless you take such huge temperature and current margins so that the efficiency of your design is completely lost. Consider also that 40 Ton/m at 20 km distance means that the conductors 100 m apart experience forces of 8000 Ton/m. The levels of strain on the Nb3Sn cables would be such that the superconducting state would be instantly lost, unless a ridiculous amount of structural steel is added as a reinforcement. Needless to say that the consequences of a quench would be catastrophic.

As a side note, someone mentioned the effects of the magnetic field on the passengers. Within some 20-30 m from the cable the field would be of the order of 1 T, which in DC conditions is completely harmless to human beings unless you happen to have a pacemaker or an aneurysm clip. However, here we're talking about a conducting object i.e. the launch vehicule moving at 9 km/s through this field; while in principle the vehicle should cut always the same amount of flux, in practice I would expect that the tiniest amount of vibration, rolling motion or field inhomogeneity would induce eddy currents of such magnitude that the launcher could simply not work.

Having said all that, the idea in itself is very nice and I admit having toyed with it myself some time ago (that's why I had all the maths already done). And yes, I work with superconducting magnets on a daily basis and I think I undertstand the implications pretty well. The startram idea is inspiring but quite impractical for the time being.

TopAstro
14th March, 2012 @ 02:39 pm PDT

@ TopAstro

I still don't understand. Why not skip the hole tube installation and simply build a superconducting round platform, and a superconducting-maybe spherical ship-to match the platform and shoot the "sphere" into space as the platform is powered up.

The 1000km tube thing is clearly impossible simply due to weather/wind, but if that much energy can be generated to hold a 1000km tube to 20km above the earth, than why not shoot a 40 ton object into space without the cumbersome tower in the way?

Plus once the spherical ship is 20 to 30km over the Earth internal engines could provide the rest of the lift into necessary orbit. Why would this not work if the tube is considered viable? And why the emphasis on a tube that seems, 1st impossible, but also a waste of energy and materials to function. Not to mention the cost of such a build and how would we build it 20km into the stratosphere?

AnOld BlackMarble
15th March, 2012 @ 01:36 pm PDT

Look at JPL the other American space program they have an excellent method of achieving orbit with out the wast of tones of fuel and rocket bodies. They have been launching Helium balloons with structures attached improving them to the point where humans can live in a safe environment in LEO. From there they plane for another craft to take people and cargo to high orbit and from there the rest of the solar system.

Joseph Mertens
15th March, 2012 @ 04:30 pm PDT

re; Joseph Mertens

Balloons don't come close to getting to LEO.

Slowburn
16th March, 2012 @ 04:27 am PDT

Why not 10G acceleration. Put fragile things like humans in a tank of water. The water would always be useful up there and the cost of sending up an additional 100 lbs of water for each person would be saved by building a 250 mile launcher instead of a 1000 mile long launcher

Mike Kling
23rd March, 2012 @ 09:53 pm PDT

I have been thinking about something like this for a long time now. However I think the most feasible way to support an inclined vacuum tube and the heavy induction coils needed to accelerate the payload is to suspend it from the roof of a pressurised envelope. The envelope would have a shape something like a very rounded mountain chain, would be at and along the equator, would start low and reach whatever height is required, ie between 12 and 20 kilometres. The way I see it, the main payload each time would be the many jigsaw-like steel parts for construction of a geostationary transit station/resort town/science city which will house the people and infrastructure needed for transshipping parts and people to mines and cities on [or rather IN] the Moon and to Mars and beyond. No people will be subjected to the g forces needed to get the building materials into orbit. Without the constraint of trying to shoot people up a vacuum tube towards a useful velocity, the system can be tailored to send millions of packages of parts and fuel supplies for the remotely controlled construction projects in space.

The geostationary city will of course be the space side power source for the space elevator which will require a lot of energy to maintain the magnetic fields holding it together, particularly at the Earth end. Once the space elevator is up and running, the costs of space exploration will fall to business as usual levels sustainable through Luna and other extraterrestrial manufacturing industries.

There is no need for 'plasma' to hold back the thinner atmosphere at the muzzle of the accelerator; a simple strip of plastic membrane will suffice because the muzzle velocity of the payload will vapourise the membrane across the hole each time. This means the strip needs to be replaced quickly to cover the hole again but that will not require 'rocket science'.

Mark A Peaty
27th March, 2012 @ 09:12 am PDT

There have been many proposals for systems that can radically lower the cost of reaching orbit. Some examples are, Laser Launchers, Space Elevators, Magnetic Launch Loops,Sky Hooks and even an Airship To Orbit. The one thing they all have in common is a requirement for multi-billion dollar infrastructure. This is unlikely to ever be undertaken. Even a billionaire space enthusiast like Elon Musk has chosen to limit his investment in reusable rockets to a couple of hundred million dollars. A technology for relatively cheap space access has been available for decades. Simply build a rocket sled track up the western slope of a high mountain like Mauna Kea in Hawaii. Frictionless air bearings would let the sled reach a thousand kilometers per hour. An orbiter equiped with air-augmented rockets could reach space using a single stage if it began firing it's engines only after being carried to four kilometers altitude and nearly mach one speeds by the rocket sled. If no one in the past half century has been willing to build such a simple system it seems unlikely that anything utilizing untried, futuristic technology will even be considered by the "Powers That Be".

DR.ZARKOF
27th March, 2012 @ 03:20 pm PDT

"...untried, futuristic technology" is the only way to go if the present technology does not deliver. But there must be a reason why "Powers That Be" step into the game. It was the Cold War and the logic of fear that started NASA; it took Kennedy's bluster to declare the Moon Shot....also a way of compensation for the humiliation at Cuba invasion shortly before. But Apollo was an "old bag" and conservative technology already proven two decades before in the War and since then in ICBMs atomic weapon delivery. I do not see any dramatic situation of this sort on the horizon (unless N.Korea starts making trouble by sending a crew to Mars or so :-).

Kennedy chose to hold back. Atomic spaceship was a REAL alternative and if it was given the same sort of focus and determination you could have "landing on the moons of Saturn [planet] instead of just "Saturn [chemical rocket] landing on the Moon" BY THE SAME TIME. That was too big even for Kennedy even though - given the same priority as Apollo - it was REALISTIC. The major reason this path was not chosen was apprehension of uncontrollable military arms race. Second reason was adverse public opinion (even though the pollution would not have gone significantly up from what was already there from air testings of H bombs - and a HUGE ship could be driven with H bombs [less pollution] and "stuffed with boron" to make the pollution negligible.)

What I want to point out is the only chance is "dual use technology": atomic spaceship was possible when there were experts around with hands-on experience with the bombs. Today it may be "laser to orbit" (with exponentials driving costs of laser down and lasers tested as weapons system. It can be "nanotubes to orbit" (Space Elevator) with independent industrial application of hight tensile nanotubes (that is the way how Bradley Edwards wanted to fund his project). [Unfortunately, the tensile strength hit a limit and is insufficient, apart from multiple design problem of the Space Elevator itself.] Space loops can be made operational as energy storage solution alternative (huge kinetic energy stored by a loop of metal frictionlessly moving in hundreds of kilometer of vacuum tube at space velocity speeds).

But Start Tram is the ONLY realistic project today with technology ALREADY available.

If a maglev grid is constructed as "Space transportation on Earth" [in ET3] or some other large maglev project (SwissMetro)...it will be only "natural" to use this "widely used" and "proven" train technology to ...reach the stars (StarTrain).

As a matter of fact, it looks even as if the inventors of maglev had REALLY StarTrain in mind originally. That would not been nothing unusual: Wernher von Braun was dreaming abou Mars colonization all way along long before he submitted V2 proposals to Nazis. Dual Use is the only way it can happen - after the new application of "established" technology becomes obvious (and the politicians do not risk too much pushing it - unlike poor Grinch).

nehopsa
16th April, 2012 @ 10:49 pm PDT

IMHO this is a bad idea as in the end this approach will cost several fortunes. It would make more sense to be greener and find a suitable mountain on or near the equator and launch from there as apart from the height gain and lower gravity the air is also thinner so there is less drag. The highest mountain in Africa is Kilimanjaro but this is a dormant volcano so in spite of its location at just three degrees south of the equator its probably not the best site. Mount Kenya might be a good location however as although its not quite as tall, part of the mountain is on the equator. 5000 metres of lift is not to be sneezed at! If Africa is too far away there is always Cayambe which is on the Pan American Highway.

Joe Bloggs
6th July, 2012 @ 04:57 pm PDT

Getting to orbit is about speed not height.

Bill Knowlton
31st July, 2012 @ 05:06 pm PDT

The maglev concept is quite practical, technically) and at today's interest rates, probably economically practical. To improve both I would suggest; 1) install the launcher on the big island of Hawaii, you get 14,000 feet for free at Mauna Loa. 2) use it for inanimate objects and run it at maximum g. 3) power the system using an Ocean Thermal Energy Concept power plant- the Mauna Loa mountain sits next to a perfect OTEC source. Considering everything, I think the Suez Canal in 1889 and Apollo in 1969 were more challenging both economically and technically.

Bill McDill
20th May, 2013 @ 01:11 pm PDT

I read through the comments. How sad that every new, completely undoable, space launch system someone dreams up has to account for terrorists. What a sad world we live in.

RelayerM31
4th May, 2014 @ 06:03 am PDT
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