Yet another lower cost launch technology.

[SAMU]

Combining several technologies that have been developed over the past few years and that have been disscussed on this board;

A 100 mile long rigid airship at an altitude of 100,000 ft. carrying a maglev launch tube.

Advantages over a land based maglev launcher are that air pressure and resistance on the payload and on the stucture is greatly reduced even over a launcher built up the side of Mt. Everest at 40,000 ft., the orientation of the airship can be changed to put the payload into any orbital inclination and the incline of launch can be adjusted somewhat for greater flexibility in launch angle, because of the above considerations and more, the cost of such a mechanism is much reduced.

Machinery for such a construction is currently well developed for maglev technology by several companies (maglev rail technology is not competitive in capital and maintanance costs with current rail technology) and is well under construction by the Zeppelin corporation (yes it is still in business) for the airship.

The program requires a five stage launch technique as follows;

Stage 1 requires conventional jet aircraft to lift cargo to;

Stage 2 a lighter than air aircraft carrier of at least 2 miles in length floating at an altitude of between 20,000 and 30,000 ft. The reason for stage 2 is to keep the fragile high lift airships of stage 2 and;

Stage 3 out of the destructive turbulence of the lower aptnosphere, Stage 3 airships lift the cargo to;

Stage 4 the maglev launch airship where the cargo is loaded onto;

Stage 5 the spacecraft.

Concept test hardware is currently available and can be deployed within 5 months and tested to propel a payload of 10 lbs. to a distance of 10,000 miles for a cost of less than $1,000,000. To keep this post as short as possible I eliminated supporting documentation and links*. Total cost of the full sized structure I have (based on supporting documentation) calculated to be $10,000,000,000. and construction time to be 8-12 years.

This could be the "Iron Horse" to space.

What do you think?

*Yahoo search maglev and Zeppelin.

[Jpax2003]

What do you think?

*Yahoo search maglev and Zeppelin.

I think I would need more data and it would not take much room to post those links if you wanted to use the url tag like this for each site.

Anyways, I see some potential problems. I like the balloons and Airships To Orbit is something I read about a few months ago. However, I am not sure a 100mi long balloon is a good idea, nor is it near as quick to change orientation as they would like. I don't like the idea of having cargo planes landing on a floating deck at 20,000 or even 30,000 feet. thunderstorms routinely exceed these levels reaching between 50,000-70,000 in supercells (also true of hurricanes). Would the balloon's structure be strong enough to survive accelerating a large mass to orbital velocity? Any failure would cause the structure to break at some point and the projectile could wreck a large portion of the structure. Not to mention the people below would rightly be worried.

You'd need lots of energy to accelerate an object that quickly... where would that energy come from? I don't think solar would be enough, and we'd then limit it to day launches. Will they use nuclear power? Again, the people down below will be worried. The ATO people may have the same political problems with airborne nukes, but a magnetic launcher may need several of them over 100 miles. The idea sounds like a combination that creates more problems. Rockets have problems with safety and efficiency but they are quick (earth to orbit in minutes), and with an economy of scale they could be as cheap as a few hundred dollars a pound. ATO are slow (couple days to over a week), but they are safe and efficient with few layovers. The maglev zeppelin idea is neither fast nor safe and while the ejector may be efficient, the intermediate steps are needlessly complicated.

Now I may be wrong, but I didn't read the articles... guess why?

BTW, Do these balloons float around the world, or can it be anchored somehow? I can see some countries having problem with a large, nuclear powered, long-range artillery system floating near their borders out of range of their defenses. And this system does not address re-entry. re-entry would be critical for developing something other than a one way transit system.

edited for spelling

[Quartermain]

A floating tube 100 miles long will be some what less than "rigid". The turbulance may be low at 100,000 feet but that doesn't mean there aren't air currents. A 100 mile ship has a lot of surface area. I sincerely doubt it would be unaffected.

There was that other project to 'float' objects into near space then using ion propulsion to achieve orbital velocity. The costs are roughly the same and it seems more likely to succeed than this project.

[SAMU]

What do you think?

*Yahoo search maglev and Zeppelin.

I think I would need more data and it would not take much room to post those links if you wanted to use the url tag like this for each site.

Well there is a lot more research I did for this essay than in just searches regarding Zeppelins and Maglev. Such as costs, construction times and test apperatus costs, construction times and availability.

Anyways, I see some potential problems. I like the balloons and Airships To Orbit is something I read about a few months ago. However, I am not sure a 100mi long balloon is a good idea, nor is it near as quick to change orientation as they would like.

Personally I dislike the mischaracterization of rigid airships as "balloons". The distinction is quite significant in this context.

Will they use nuclear power?

Hardly neccisarily.

Rockets have problems with safety and efficiency but they are quick (earth to orbit in minutes), and with an economy of scale they could be as cheap as a few hundred dollars a pound.

Could be but are not by a factor of thousands to tens of thousands of times.

ATO are slow (couple days to over a week), but they are safe and efficient with few layovers. The maglev zeppelin idea is neither fast nor safe and while the ejector may be efficient, the intermediate steps are needlessly complicated..

What, exactly is the "needless compexity"compared to the complexity of the hundreds of millions of dollars of explosive control apperatus needed by rockets?

Now I may be wrong, but I didn't read the articles... guess why?

Duuh, because yuhh din't research duh "complexities" involved before yuh posted yu'r opposition?

BTW, Do these balloons float around the world, or can it be anchored somehow? I can see some countries having problem with a large, nuclear powered, long-range artillery system floating near their borders out of range of their defenses.?

Good point, Military usage would be that it could launch tons of warheads to anywhere on Earth with the accuracy of any of the "smart bombs" that it launches and if maintained over the continental US it would be invulnerable to any but the highest flying aircraft, antiaircraft or intercontinental ballistic missiles possessed by only the most advanced military powers.

The system does not address re-entry. re-entry would be critical for developing something other than a one way transit system.

Cargo, as mentioned in the OP, does not have to reenter (intact).

"What makes them rocketships go up?"
Heck, the economics would take so long to explain to ya that we'd never git to the aerodynamics.

[Jpax2003]

Personally I dislike the mischaracterization of rigid airships as "balloons". The distinction is quite significant in this context.

What would you prefer? Airship is fine for me, or can we call it a Bouancy Principle Lift Vehicle or BPLV?

Will they use nuclear power?

Hardly neccisarily.

OK, what means will be employed to electrify the magnetic levitation rails and freight skids?

Rockets have problems with safety and efficiency but they are quick (earth to orbit in minutes), and with an economy of scale they could be as cheap as a few hundred dollars a pound.

Could be but are not by a factor of thousands to tens of thousands of times.

Read about rockets and economy of scale here.

ATO are slow (couple days to over a week), but they are safe and efficient with few layovers. The maglev zeppelin idea is neither fast nor safe and while the ejector may be efficient, the intermediate steps are needlessly complicated..

What, exactly is the "needless compexity"compared to the complexity of the hundreds of millions of dollars of explosive control apperatus needed by rockets?

Turbojet planes landing and stopping to unload cargo at 30,000ft, then that cargo being loaded, lofted and exchanged yet again at 100,000ft. Can these maintain station with a variable jetstream jostling them around? Would it be economically feasible to locate these away from the jetstreams (and away from customers)? If you do plan to keep this carrier deck at 30,000ft in the northern midlatitudes in the US, how do you plan to land air freighters in a 300mph crosswind? For comments about the cost of rocket motor and avionics, go to the previously mentioned website.

Now I may be wrong, but I didn't read the articles... guess why?

Duuh, because yuhh din't research duh "complexities" involved before yuh posted yu'r opposition?

Personally, I dislike that mischaracterization... that behavior is uncalled for.

Anyways, no, because you didn't link to your own resources. It's hard to argue a datum without having access to it. While someone could find information regarding this proposal, how would any person know if it was the same information used by you? You give me too much credit, for I am not clairvoyant.

BTW, Do these balloons float around the world, or can it be anchored somehow? I can see some countries having problem with a large, nuclear powered, long-range artillery system floating near their borders out of range of their defenses.?

Good point, Military usage would be that it could launch tons of warheads to anywhere on Earth with the accuracy of any of the "smart bombs" that it launches and if maintained over the continental US it would be invulnerable to any but the highest flying aircraft, antiaircraft or intercontinental ballistic missiles possessed by only the most advanced military powers.

What's with the crying? Anyways, if you want to get your dirigible plan on the international outlawed list, then by all means, define its use as a weapon of mass destruction. Are you trying to start a new arms race and cold war?

The system does not address re-entry. re-entry would be critical for developing something other than a one way transit system.

Cargo, as mentioned in the OP, does not have to reenter (intact).

Then at best it is only half of a space program. It wouldn't win the X-Prize. I didn't see anynote about cargo no re-entry on your OP. Which reminds me...

Concept test hardware is currently available and can be deployed within 5 months and tested to propel a payload of 10 lbs. to a distance of 10,000 miles for a cost of less than $1,000,000. To keep this post as short as possible I eliminated supporting documentation and links*. Total cost of the full sized structure I have (based on supporting documentation) calculated to be $10,000,000,000. and construction time to be 8-12 years.

If you click on the aforementioned link, you will see that John Walker estimates start up costs for Rocket A Day to be in the neighborhood of less than .5 Billion, 1/20 the cost of your project.

"What makes them rocketships go up?"
Heck, the economics would take so long to explain to ya that we'd never git to the aerodynamics.

This does not appear to be a signature... is there a reason you put this in your response to me?

edited to add last comment

[SAMU]

Personally I dislike the mischaracterization of rigid airships as "balloons". The distinction is quite significant in this context.

What would you prefer? Airship is fine for me, or can we call it a Bouancy Principle Lift Vehicle or BPLV?

If "airship" is ok with you let's just keep calling it an airship and avoid this obfustication.

Will they use nuclear power?

Hardly neccisarily.

OK, what means will be employed to electrify the magnetic levitation rails and freight skids?

How about hydroelectric?

[sts60]

... the orientation of the airship can be changed to put the payload into any orbital inclination...

Launch azimuth isn't really the important thing in determining orbital inclination. Launch latitude is. Of course, an airship should be able to go to any convenient launch latitude.

It sounds like fun, but a cargo jet to land or somehow dock with an LTA, which docks with another LTA, which docks with another LTA a hundred miles long? That's a lot of steps, a lot of individual flying things which have to stay in the air a long time. And that one-hundred-mile-long zeppelin is hard to imagine. Though I'm no expert on LTAs, let alone high-altitude ones.

Concept test hardware is currently available and can be deployed within 5 months and tested to propel a payload of 10 lbs. to a distance of 10,000 miles for a cost of less than $1,000,000.

You can demonstrate this system within five months? Really? What part, exactly?

And by "10,000 miles", did you mean into a 10,000 mile orbit, or just an arc with a 10,000 mile apogee?

Tried Yahoo and Google for "zeppelin" and "maglev", but did not find the concept you mentioned. Could you post a specific link using the

url=<link goes here>]<short descriptive label>[/url]

format?

[Demigrog]

While this is an interesting idea, it suffers from the same problem that has kept conventional rockets from becoming cost effective: we simply are not launching enough spacecraft to justify billions of dollars on a new launch system.

Speaking of googling for maglev and zeppelin, has anyone noticed that the good old "+" operator in search terms isn't being honored? Searching for "+maglev +zeppelin" had a CNN article on maglev trains as its #1 result, even though "zeppelin" did not appear at all in the article. My guess is that CNN paid to have their results bumped up; that is marginally acceptable at the best of times, but when the result flatly does not meet the search criteria, that really ticks me off. [/rant] Oh, and I didn't find anything relevant on the first 4 pages of search results, so I got lazy and gave up.

[wedgebert]

How about hydroelectric?

How exactly do you set up a hydroelectric powerplant at 30,000 - 100,000 feet?

[SAMU]

I thunk this up myself so I don't know if anyone else has come up with this idea and put a website up.

Concept test hardware is currently available and can be deployed within 5 months and tested to propel a payload of 10 lbs. to a distance of 10,000 miles for a cost of less than $1,000,000.

You can demonstrate this system within five months? Really? What part, exactly?

And by "10,000 miles", did you mean into a 10,000 mile orbit, or just an arc with a 10,000 mile apogee?

First I would borrow or rent a rail gun from this group or more likely another group:
http://www.rit.edu/~dih0658/ This particular rail gun can launch projectiles up to 4 km/s.

This gun is a rather primitive one compared to one other I have seen demonstrated on on educational TV in the context of a disscussion on meteor impact. It's owned by the military and is mostly classified so I can't find a picture of it online but it is a beaut, three stories long, very refined looking, total capabilities are classified but it fired a projectile into a bed of sand at a speed revealed to be 4000 mph.

Lift the rail gun with a Zeppelin, blimp or balloon http://spot.colorado.edu/~dziadeck/a...ufacturers.htm to an altitude where air resistance is minimized enough so that the projectile can travel as far as possible. At 4km/s at 45 degrees it should leave the atmosphere and go as far as 10,000 miles (downrange) or more.

How about hydroelectric?

How exactly do you set up a hydroelectric powerplant at 30,000 - 100,000 feet?

Actually I was joking. But since you ask you could beam the power up via microwave transmission. Or you could beam the power down from solar electric producing satelites as you would not lose so much to the aptnosphere because of the airships altitude. But I was thinking more along the lines of conventional gas turbine electric generation onboard the airship.

While this is an interesting idea, it suffers from the same problem that has kept conventional rockets from becoming cost effective: we simply are not launching enough spacecraft to justify billions of dollars on a new launch system.

The reason we don't launch many spacecraft is because they are so expensive to launch. While capital investment in the airship launcher may seem high, it is comparable to development costs of any new launch technology and the primary technologies on which it is based are already well developed and are far safer than rocketry.

The initial cost of the launcher can be amortized over the lower per launch cost which is more than conventional air frieght but several orders of magnitude less than the current cost of rocket based spacecraft launch.

Increased numbers of launches, by virtue of lower launch cost, results in the ability to increase payload reliability by what may at first strike you as a counterintuitive proccess. By launching more less reliable spacecraft total reliability is increased for the same cost. For example, let us just say that a SONY VCR is 2 times more reliable than an Emerson, but a SONY costs 3 times more than an Emerson. So 3 Emerson VCRs will give you the 50% more reliability for the same cost as one SONY.

If the proposed next generation of launch technology does not reduce launch costs by the orders of magnitude described above, no one alive today will live to see the vast resources available in space put to much practical use beyond telecomunications (ie more TV).

But if the costs can be reduced by the orders of magnitude described above then space will be opened up like the American west was in the age of the railroad, ie covered wagon to spacecraft in a single liftime or, as in this case, the cradle of humanity to intergalactic civilization in a single lifetime.

[Demigrog]

The reason we don't launch many spacecraft is because they are so expensive to launch. While capital investment in the airship launcher may seem high, it is comparable to development costs of any new launch technology and the primary technologies on which it is based are already well developed and are far safer than rocketry.

Definitely a catch-22. The "if you build it, they will come" approach can work, but raising billions of dollars is simply impossible without government involvement, which means having a specific goal in mind. For the new launcher to be built, it would have to be part of a larger program like a permanent lunar colony that actually needed regular and frequent flights and provided the funding. Barring that, the cost will have to come down first; waiting for improved technology, in other words.

From a mechanical standpoint, it will be very hard to have a shape 100 miles long that is flat and rigid enough for a maglev launch and is also lightweight and airborne. Frankly, the engineering would probably be harder than a space elevator.

The initial cost of the launcher can be amortized over the lower per launch cost which is more than conventional air frieght but several orders of magnitude less than the current cost of rocket based spacecraft launch.

Sure, it might pay for itself eventually, but that still doesn’t make it any easier to find the upfront money to build it in the first place. Venture capitalists might fund a hundred million dollar project (if they really trusted the management and engineering talent), but not billions (particularly in the Space industry).

But if the costs can be reduced by the orders of magnitude described above then space will be opened up like the American west was in the age of the railroad, ie covered wagon to spacecraft in a single liftime or, as in this case, the cradle of humanity to intergalactic civilization in a single lifetime.

The difference being that people saw great value in moving west and owning a few hundred acres of their own, whereas there probably won’t be a mass movement to live in cramped, dangerous artificial habitats on a barren rock. Return on investment in space exploration and colonization is slow at best.

To be clear, I am a strong advocate of space research and colonization, but I support doing it in small incremental stages. Establish self-sufficient, sub-orbital space tourism, and we’ll eventually get cheap orbital access as technology advances. Rushing things, we’ll just spend a lot of money on technology that will be obsolete before it flies.

[Eye-Zee]

Combining several technologies that have been developed over the past few years and that have been disscussed on this board;

A 100 mile long rigid airship at an altitude of 100,000 ft. carrying a maglev launch tube.

Stop right there. What contiguous structures do we have nowadays that are anywhere _near_ that long? Oil/gas Pipelines? Asphalt roads? Is derigible structure scalable to that size with any kind of stability? Where would you even _build_ this thing? What kind of infrastructure would you need to develop?

And from later on -
It sounds like getting the fuel alone for gas-electric turbines at 100,000 feet to power maglev launchers is going to rivial that of direct launch into space.

I'd personally much rather see a space elevator.

[Irishman]

First let me say you have some creative thought. Creative thought is definitely a plus. So don't take all this criticism too harshly. Yes, there's a lot of valid points to consider, but that's not a criticism of you, just your idea.

Increased numbers of launches, by virtue of lower launch cost, results in the ability to increase payload reliability by what may at first strike you as a counterintuitive proccess. By launching more less reliable spacecraft total reliability is increased for the same cost. For example, let us just say that a SONY VCR is 2 times more reliable than an Emerson, but a SONY costs 3 times more than an Emerson. So 3 Emerson VCRs will give you the 50% more reliability for the same cost as one SONY.

This analogy seems flawed. Launch services aren't like VCRs. For one thing, if your VCR fails to run, you can plug your tape in the next VCR. If your launch service fails to perform, you typically have destroyed the payload. Suppose my proposed payload is a one of a kind $100,000,000 planetary probe. Suppose I have two possible launch systems. One is 90% reliable, one is 99% reliable. That 10% of the time I destroy my one of a kind system is going to be very painful to me. Suppose my payload is one of a set of telecommunications satellites. If I lose my payload, I still have to build another one. Even if the design cost has been paid, there's still substantial cost in building and testing a replacement. That gets expensive. So that 9% reliability difference is going to be valuable to me. Is the cost differential in launch systems enough to offset the extra losses I'll incur?

Power use is going to be substantial. Even if you don't need much for thrust for the airships (???), you will need a substantial amount for the maglev launcher. Running off on-board power plants running on fuel requires supplying the fuel. Microwave transmission of the power means care in aligning the transmitters. Neither seems trivial.

Shuffling payload from one to another to another luanch system is inefficient. Every transfer is a risky endeavor. All it takes is one error and you have a kinetic strike device plummeting at the ground. Maybe you'll stationkeep over the ocean? (Did you see the pictures of the satellite that got trashed because of one sloppy mistake in handling? Someone borrowed the anchor bolts holding it in place and forgot to log it or replace them, and the next shift crew didn't realize they were missing before performing a rotation of the satellite for testing. It fell off the framework and smashed into the ground.)

And I don't know about even building a 100 mile long airship, nevermind making it to carry a maglev rigid enough to work.

First I would borrow or rent a rail gun from this group or more likely another group:
http://www.rit.edu/~dih0658/ This particular rail gun can launch projectiles up to 4 km/s.

This gun is a rather primitive one compared to one other I have seen demonstrated on on educational TV in the context of a disscussion on meteor impact. It's owned by the military and is mostly classified so I can't find a picture of it online but it is a beaut, three stories long, very refined looking, total capabilities are classified but it fired a projectile into a bed of sand at a speed revealed to be 4000 mph.

What size payload are we talking about? Is that scalable? How much power required to launch a 100kg satellite? A 100kg satellite? a 10,000 kg payload?

Also, while railguns allow high velocity speeds, one of the big concerns about launches is the acceleration on the payload. One of the advantages of rockets is they apply the acceleration all the way to orbit, so they can use a lower acceleration. A rail gun must impart all the energy prior to leaving the rail, and then coast ballistically the rest of the way to orbit. Thus you either have very high accelerations, very long guns, or both. While some payloads can withstand higher accelerations, things like electronics are often more sensitive than humans. All well and good to build a launch system that is cheaper than rockets if it can't be used for a substantial fraction or even majority of the launch needs. That's a challenge whether the rail guns are on airships or on mountainsides.

At 4km/s at 45 degrees it should leave the atmosphere and go as far as 10,000 miles (downrange) or more.

How do you get this rail gun at 45 degrees? I am guessing you have a gently curved section near the end. I can't imagine suspending the whole length from the airship at an angle. Or flying at an angle.

Is 10,000 miles down range the same as low earth orbit? How useful is 10,000 miles down range? Why spend a week to transfer the payload to 50,000 feet only to crash it 10,000 miles down range, when you could just fly it there directly?

[SAMU]

This analogy seems flawed.

You misread what I wrote. I didn't mean that the launch method was less reliable but that the payload (the VCR) can be less reliable and less expensive and need not be so reliable that it is one enormously expensive and one of a kind.

Power use is going to be substantial.

Do you understand the power differential between this method and the rocket launch method? In a rocket you have to accelerate to orbital speed all the fuel that you will use for the flight, a powerful enough engine to thrust all that fuel and the engine to that speed and you have to throw away, or totaly rebuild in the case of the Space Shuttle, the engine and 90% of the launch vehicle. In the case of the maglev launcher you leave the fuel, the engine and the fuel tanks behind to be reused as often and reliably as a crosstown shuttle.

And I don't know about even building a 100 mile long airship, nevermind making it to carry a maglev rigid enough to work.

Air currents are so small at those altitudes that the airship is not so much flying in the upper aptnosphere as it is imbeded in it. So, flexion of the structure is well within our capaility to maintain required straightness.

What size payload are we talking about? Is that scalable? How much power required to launch a 100kg satellite? A 100kg satellite? a 10,000 kg payload?

Yes it is not only scaleable but the technology for 100 ton payloads is already well developed.

Also, while railguns allow high velocity speeds, one of the big concerns about launches is the acceleration on the payload.

Which is why the launcher has to be so long.

While some payloads can withstand higher accelerations, things like electronics are often more sensitive than humans.

Not true. In fact I am right now holding in my hand a hard drive from one of my computers that says right on it "rated to 75 Gs." Now, as you may know, a hard drive is one of the components of your computer that is most sensitive to accelerative forces and 75 Gs would break most of the bones in your body and rupture many of your organs. Not that 75 Gs is remotely contemplated for this launcher. 10 Gs is perfectly sustainable if you are flat on your back. I have ridden a centifuge at NASA at 10 Gs for several minutes myself. 10 Gs is what you will need to reach orbital speed in the length of the launcher.

How do you get this rail gun at 45 degrees? I am guessing you have a gently curved section near the end. I can't imagine suspending the whole length from the airship at an angle. Or flying at an angle. .

Again you misread what I wrote. The rail to be used for a test of concept as seen in the picture I did post a link to is clearly capable of being carried in any orientation by nearly any airship currently available. And, as I wrote, the 10,000 mile test of concept distance is not orbital but suborbital. The airship launcher must accelerate the payloads to more than 4 times that speed but will have over 10,000 times the distance to do it ie a 50 ft long railgun compared to a 100 mile long launcher.

[Sammy]

Forget the idea of beaming microwave power up or down.

Beaming up power suffers from heavy power losses going thru the atmosphere, and would create massive amounts of ozone -- a definite no-no (one of the reasons the idea of orbiting solar power sats has died).

Beaming power from space to the launch vehicle avoids the path loss/ozone probs, but suffers from another problem shared with the beaming down approach. You have to keep the beam focused on the reception device. The drifting launch vehicle will be a hard target, and missing the target will not only deprive the vehicle of power, it may cook the crew!

I would have to rank this approach with the hydroelectric idea :P

[Eye-Zee]

A related but substantially different spin on this is being used by some of the X-prize competitors. They intend to float their rockets as high as possible using baloons before kicking the engines on.

I can see a potentially scaled up version of balloon-assisted launch for serious cargo payloads, assuming you could control launch attitude really well. It probably wouldn't be re-usable, since when the rocket did fire, it'd torch the baloons, but if you could lift tens of tons to 100,000 feet before kikcing on the engines, you'd have a potential huge savings in cost to orbit. Whether it would offset the cost of the balloon system, I have no idea.

[russ_watters]

Combining several technologies that have been developed over the past few years and that have been disscussed on this board;

A 100 mile long rigid airship at an altitude of 100,000 ft. carrying a maglev launch tube.

Stop right there. What contiguous structures do we have nowadays that are anywhere _near_ that long? Oil/gas Pipelines? Asphalt roads? Is derigible structure scalable to that size with any kind of stability? Where would you even _build_ this thing? What kind of infrastructure would you need to develop?

Hey, and why don't we assume its a skinny 1 mile wide: that's 11.5 trillion cubic feet of hydrogen.

[russ_watters]

While some payloads can withstand higher accelerations, things like electronics are often more sensitive than humans.

Not true. In fact I am right now holding in my hand a hard drive from one of my computers that says right on it "rated to 75 Gs."

That's 75g instantaneous, ie in an impact. Not 75G sustained.

Air currents are so small at those altitudes that the airship is not so much flying in the upper aptnosphere as it is imbeded in it. So, flexion of the structure is well within our capaility to maintain required straightness.

Have you done any calculations on this? A tiny difference from one side to the other gets amplified by a 100 mile lever - the forces involved are enormous.

[Irishman]

SAMU, you are correct, there has been miscommunication.

You misread what I wrote. I didn't mean that the launch method was less reliable but that the payload (the VCR) can be less reliable and less expensive and need not be so reliable that it is one enormously expensive and one of a kind.

Ah, yes, I misunderstood. This is part of the philosophy behind "faster, cheaper, better". A lot of smaller, less expensive missions instead of few, big missions. More Pathfinders, less Cassinis. In theory, it means you are less susceptible to individual losses, and can recover quicker. In practice, NASA still gets a black eye from any loss, and the pace of missions means future missions that build on the current ones are already in works, meaning loss still impacts the near future recovery. But it is a valid concept.

Do you understand the power differential between this method and the rocket launch method? In a rocket you have to accelerate to orbital speed all the fuel that you will use for the flight, a powerful enough engine to thrust all that fuel and the engine to that speed and you have to throw away, or totaly rebuild in the case of the Space Shuttle, the engine and 90% of the launch vehicle. In the case of the maglev launcher you leave the fuel, the engine and the fuel tanks behind to be reused as often and reliably as a crosstown shuttle.

Waste is not the issue. Overall power/resource use is not the issue. I was referring to having the power available to drive the maglev. It will take a substantial amount of power to operate a maglev large enough to launch a reasonably sized payload to orbit, even if launched from 100,000 ft. It is true a rocket wastes energy lifting the fuel needed for higher elevations and to carry the tanks to carry the fuel, tanks that are largely destroyed. But it is much easier to fill tanks with fluid while on the ground than to generate electrical power in an airship.

Of course, efficient power cells lining the top of the airship and some sort of storage system (i.e banks of capacitors) might be workable, but could they develop the power required? That is a question for R&D I suppose.

Air currents are so small at those altitudes that the airship is not so much flying in the upper aptnosphere as it is imbeded in it. So, flexion of the structure is well within our capaility to maintain required straightness.

I beg to differ. Materials are not infinitely rigid. Materials that are stiff in short lengths are bowed by long lengths. Structural design will be crucial. I just can't see building a 100 mile long structure that will not be susceptible to bending from imparted loads. Note that it is not just wind you need to account for. Even if there is zero wind, there are still loads imparted by people walking around, by vehicles landing/docking, by moving payloads around, by pumping fuel or whatever. Water and consumables for the crew, since the airships never land. I regularly experience my desk shaking to a noticable degree by people walking by, and I'm on the second floor of a four story building. Vibration loads are not negligible. This problem may not be insurmountable, but it certainly is not trivial.

Regarding the example you provided, we clearly miscommunicated. You were pointing out a working rail gun for a demonstrator test, that could be carried by a conventional airship. My questions had to do with scaling up. A fifty foot long rail gun is one thing - a 100 mile long rail gun is another. I concede that a big enough balloon can lift anything, I just am concerned about what "big enough" is for a rigid airship including a rail gun long enough and big enough around to launch something like an Apollo capsule, nevermind something like HST. Similarly, a 50 ft rail gun could be mounted at an angle to achieve elevation, but a 100 mile long rail gun would not. The airship probably shouldn't be flying at a 45 degree angle. See where the confusion arose? We were speaking about different aspects.

Regarding sensitivity to g forces, we have two aspects to consider. One is shock loading, the other is sustained acceleration. Neither are pretty. I know I wouldn't care to ride a 10g jolt for long or very often. As for which is more sensitive, perhaps I am not best informed for rating such. I'm an ME by training, not EE. I just think about things like IC chips with very tiny wires and such and shock loads. Maybe I'm wrong.

Total cost of the full sized structure I have (based on supporting documentation) calculated to be $10,000,000,000. and construction time to be 8-12 years.

Is that calculated by NASA's standard development cost calculator? $10 Billion over a 12 year development/construction time seems reasonable to me for coming up with a completely new launch system. How does that compare with a fleet of expendables? A new reusable vehicle (that really is reusable)? A space elevator (and the subsequent trade offs)?

[Jpax2003]

I just did a quick calculation. If your 100 mile long airship is floating with an angle of 45° then the vertical height from top to bottom is over 370,000 ft. In other words, with one end dragging the ground, the other would be almost 4 times higher than you're planned ejection altitude, over 70 miles up. Or, alternately, if you want ejection at 100,000 ft for bouyancy reasons, you're 45° angle would bury the catipult head over 270,000 feet deep (51 miles). Or you could drag the bottom at sea level and the top at 100,000 ft with an injection angle of about 10º to 15º...

[SAMU]

One of the prime advantages in maglev technology an airship technology is that they are both examples of technology that have billions of dollars of capital already invested in their developement but they both continue to be impractical for the purposes that they are being developed for. For this reason they are technologies that are searching for a buyer. So it is a buyers market. That means that the developers should be very interested in making the hardware easy to buy. They even subsidize some of the costs of construction of practical uses for their products.

The maglev technology was recently used for a 30 km line at 430 kph from Shanghai airport to Shanghai for $1.2 billion and was subsidized by the German government where much of the hardware was manufactured.
http://www.gluckman.com/Maglev.html

The technology is not competitive with conventional high speed rail because of the capital investment cost. It is however subsidizeable for short lengths as demonstrations of it. Subsidizing a 100 mile length for a first step space launcher could be very attractive to developers particularly if several producers and several government's funding shared the costs and the glory.

Just to mention, a 100 mile long airship would, of course, require some small amount of dynamic control to maintain stability, ie thrusters along its length to counter the minute air currents which would seek to bend it. Of course there are technical requirements for every aspect of such a program. None of them are insurmountable or what could even be called "problems", they are requirements. For example; If a hotel were built in space itself, it would be required to have a minimum degree of reliability to reliably sustain life. That minimum is easier, less expensive and more reliable when you can inexpensively lift the construction material to the construction site. When you use very expensive rockets, where every ounce that you lift costs thousands of dollars to lift, you get the very thin walled, rink-a-dink, unreliable, spacecraft, materials and habitats that we have today.

[Demigrog]

Subsidizing a 100 mile length for a first step space launcher could be very attractive to developers particularly if several producers and several government's funding shared the costs and the glory.

Unfortunately, there is a considerable difference between the maglev technology of a train and the maglev technology required to launch a spacecraft. Namely, about 27400 kph for a 300 km orbit. A better way to estimate the price might be to look at existing proposals for railgun-type launchers operating from earth.

[Jpax2003]

Just to mention, a 100 mile long airship would, of course, require some small amount of dynamic control to maintain stability, ie thrusters along its length to counter the minute air currents which would seek to bend it.

Actually, it can't be straight. I think the 100 miles would need to be curved to compensate for coriolis. And if the rail is 100 miles long it will stretch across about 4.5 degrees of earth's circumference. If all points float at the same altitude, it will need a downward (inward) curvature, necessitating a centripetal force to keep the payload on track. That means your payload will need to run under the rail. Unless you want it to launch prematurely. Since you are magnetically levitating it, what's going to hold it down? Or are you going to bend your floating rail inwards to straighten it out?

BTW, what is the frictional heating experienced by your paylod module as it moves through the atmosphere. Most rocket launches climb way up before they rotate toward the horizontal to increase to orbital velocity. However, your plan is to eject it from your rail at orbital velocity at low altitude at such an angle that it must continue going through the atmosphere a long ways before it reaches the dragless vacuum. And what is the actual ejection velocity required in order to reach orbital altitude with orbital velocity?

That minimum is easier, less expensive and more reliable when you can inexpensively lift the construction material to the construction site. When you use very expensive rockets, where every ounce that you lift costs thousands of dollars to lift, you get the very thin walled, rink-a-dink, unreliable, spacecraft, materials and habitats that we have today.

What is your economic model? I suggested figures demonstrated by John Walker in Rocket a Day. Surely you have worked this out far enough to guess how much it would take to amortize the large startup costs you mentioned, while maintaining a low launchweight cost. Using, JW's format, he postulates a possible program that could get a grand total of 2,000,000 kg to orbit for $1,250,000,000 over 1000 launches ($1.25M/launch) over the course of less than 3 years costing the consumer $625/kg.

[Excelsior]

A hundred mile long airship sounds just too big and far fetched to be true.

[PeterFab]

And if the rail is 100 miles long it will stretch across about 4.5 degrees of earth's circumference.

1.4 degrees actually.

[SAMU]

Unfortunately, there is a considerable difference between the maglev technology of a train and the maglev technology required to launch a spacecraft.

Well, there's a lot of difference between a Cadillac and a Volkswagon but theres' a lot that's the same too.

As for ground based maglev launchers; Even a cursory examination of the requirements involved render it far more technically infeasable and expensive.

As mentioned, a ground based launcher cannot be reoriented for varied orbital inclinations, it must launch at a steeper than an airship launch to get above the atmosphere in as short a time as possible to minimize air resistance, even if launched from the top of Everest the spacecraft would still have to withstand air resistance that no spacecraft design has ever been contemplated to withstand, launched at 100,000 ft it would have to withstand 1/10th of that.

As well you have to curve the track to minimize having to either tunnel through hundreds of miles of rock to depths that have never been reached before or building hundreds of miles of towers many miles high to support it or both and note I wrote "minimize", you would still have to build both tunnels and towers to currently unheard of specifications just to make either less impossible. While the Taipei 101 tower at 1,671 ft cost $1.7 billion, We're talking towers that are so tall and that have to be so rigid to withstand wind pressures to maintain the required straightness for launch that each one would cost more than the entire Apollo program, have foundations heavier than the Hoover Dam and we are talking hundreds if not thousands. The tunnels would be much longer than the The $15 billion Channel Tunnel which is only 31 miles long. Not to mention that building on mountains is building on intrinsicly unstable soil only it's not soil, it's rock. The Channel tunnel was built through fairly soft earth.

Also, the curvature of the launcher will add a centrifugal acceleration to the payload which does not add to the speed of it and at the speed required to penetrate the atmosphere and achieve orbit the curvature will require a compromise between the many factors of acceptable centrifugal acceleration from curvature and acceptable acceleration for speed which will entail a much longer track length, increased cost, deeper tunnels and higher towers etc. to achieve the same launch speed as simply a higher launch platform will achieve.

These are some of the magnitudes of capital invesment requirements for ground based maglev launch that have kept it from being a viable launch method despite of the fact that in the ideal there is much to favor the concept of maglev launch.

[wedgebert]

I have a more practical question. What do you use to keep the airship afloat with? You don't want a 100 mile long Hindenburg, and Helium is pretty rare on Earth. Using russ_watters calcuation of volume, you're going to need over 11 trillion cubic feet of gas.

Using the 1986 price of Helium of $37.50 per 1000 cubic feet, that's over four hundred billion dollars in helium costs alone just for the initial launch volume. Now you also have to constantly refill the airship because it's near impossible to keep helium from leaking because it's so small. Plus I doubt we have enough helium to come close to filling it up the first time.

[Zachary]

I have a more practical question. What do you use to keep the airship afloat with? You don't want a 100 mile long Hindenburg, and Helium is pretty rare on Earth. Using russ_watters calcuation of volume, you're going to need over 11 trillion cubic feet of gas.

Using the 1986 price of Helium of $37.50 per 1000 cubic feet, that's over four hundred billion dollars in helium costs alone just for the initial launch volume. Now you also have to constantly refill the airship because it's near impossible to keep helium from leaking because it's so small. Plus I doubt we have enough helium to come close to filling it up the first time.

Maybe we'll have to wait until fusion power becomes a popular method of power generation - there'll be a lot of helium floating around then

[Jpax2003]

And if the rail is 100 miles long it will stretch across about 4.5 degrees of earth's circumference.

1.4 degrees actually.

Oops, I used the diameter instead of the circumference, thought it seems kinda large.

I have a more practical question. What do you use to keep the airship afloat with? You don't want a 100 mile long Hindenburg, and Helium is pretty rare on Earth. Using russ_watters calcuation of volume, you're going to need over 11 trillion cubic feet of gas.

Using the 1986 price of Helium of $37.50 per 1000 cubic feet, that's over four hundred billion dollars in helium costs alone just for the initial launch volume. Now you also have to constantly refill the airship because it's near impossible to keep helium from leaking because it's so small. Plus I doubt we have enough helium to come close to filling it up the first time.

Maybe we'll have to wait until fusion power becomes a popular method of power generation - there'll be a lot of helium floating around then

Or Fission, remember alpha radiation is helium nuclei. I guess SAMU will need nukes after all, just like I said earlier.

[wedgebert]

Going to take an awful lot of nuclear power to produce that much helium.