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hi,
i sent my new lauch method idea few days ago to forum.
you can find details of idea with sample pictures at
http://www.yablam.org/sum_eng.htm]www.y … um_eng.htm.
now i think to combine yablam with magnetic catapult launch method. i did picture, you can see here ;
http://www.yablam.org/yablam_magnetic_c … tapult.GIF
this method yablam will be 90km high.
payloads will ascend on hose with electric power.
rockets will carry a magnetic catapult to 85km high too.
at 85km high, temperature is -90c, so it is easy to run super-conductor magnetic catapult.
magnetic catapult can not be run at ground because air friction will burn payload. but if we carry capatult to 85km high we can accelerate orbital speed with catapult !
so difference between launching 1 ton or 5 ton payload to orbital speed will be only more electric power used. electric is produced at ground.
i am not sure is 85km high is enough because of air friction. maybe 50km is enough or it must be minimum 150km.
i am not sure minimum length and mass of a super conductor magnetic catapult that will accelerate 5 ton payload to 7.7 km/s orbital speed.
i am not sure what is maximum G that electronic payloads can handle. as i know maximum G for man is 6G.
magnetic catapult is old idea for payload launching at moon. because there is no air on moon.
advantages of this method ;
- no need to use chemical fuel to accelerate orbital speed.
- we use electric to accelerate orbital speed. mass of electric power is 0kg.
- we have %100 REUSABLE launch structure.
- ONLY cost of launching payloads is fuel and electric. we dont destroy any structure each time we launch new payload.
some links on magnetic catapult ;
http://www.memagazine.org/backissues/fe … ...ds.html
works of nasa related magnetic catapult.
http://www.magplane.com/html/pdf/5_21_0 … _21_01.pdf
http://www.davidszondy.com/future/space … onies2.htm
http://www.spacelaw.com.au/content/expl … tation.htm
note:
all my sentences and numbers are ONLY plain idea, no calculation or research done.
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Ummm... you want to lift the entire magnetic railgun up to near orbital altitude with continuous rocket firing? The railgun powerful enough to reach orbital velocity without killing a crew would need to be tens of kilometers long and weigh thousands of tonnes, there is no way you could lift such a thing to altitude with rockets.
Put the railgun on the ground, and keep it short, just like 10km or so and use it to launch spaceplanes. If your spaceplane is powerd by a Scramjet engine, such an arrangement would be very efficent.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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some links about catapult idea ;
http://www.nationmaster.com/encyclopedi … ass-driver
http://www.oz.net/~coilgun/theory/elect … roguns.htm
http://www.nationmaster.com/encyclopedi … levitation
http://www.tribuneindia.com/2000/200004 … cience.htm
But alas... these devices would be of no use on the earth. The reasons — strong gravitational pull and high atmospheric resistance! But this system could efficiently be employed on the moon of an asteroid. It has been suggested that the mass driver for the moon would be around a kilometre long and provide acceleration of 130g to the contents, giving lunar escape velocity of 2.4 km/sec.
http://www.nationmaster.com/encyclopedi … ...ansport
Once multiple bases have been established on the lunar surface, they can be linked together by permanent railway systems. Both conventional and magnetic levitation (Mag-Lev) systems have been proposed for the transport lines. Mag-Lev systems are particularly attractive as there is no atmosphere on the surface to slow down the train, so the vehicles could achieve velocities comparable to aircraft on the Earth.
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Ummm... you want to lift the entire magnetic railgun up to near orbital altitude with continuous rocket firing? The railgun powerful enough to reach orbital velocity without killing a crew would need to be tens of kilometers long and weigh thousands of tonnes, there is no way you could lift such a thing to altitude with rockets.
Put the railgun on the ground, and keep it short, just like 10km or so and use it to launch spaceplanes. If your spaceplane is powerd by a Scramjet engine, such an arrangement would be very efficent.
there is no atmosphere friction at orbital altitude. this will make railgun tall vey small i guess. Check this link please.
http://www.tribuneindia.com/2000/20000420/science.htm
But alas... these devices would be of no use on the earth. The reasons — strong gravitational pull and high atmospheric resistance! But this system could efficiently be employed on the moon of an asteroid. It has been suggested that the mass driver for the moon would be around a kilometre long and provide acceleration of 130g to the contents, giving lunar escape velocity of 2.4 km/sec.
if 1km railgun is enough for 2.4km/sec, 2-3 km maybe enough for 7.7km/s orbital speed. and 3km railgun can be ascended to 40-50km high (i am not sure optimal target altitude maybe 100 or 200km) by many small rockets. but furl ıf rockets must be pumped from ground realtime, so rockets will not carry all fuel that they will burn.
i know 130g is very much for human but it may be tolerable for satellites.
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From a presentation about a maglev system I remember for 20g acceleration to orbital speed you need 300km track. Those people wanted to levitate the maglev by superconducting elecrodynamic tethers, so it would stand at angle with one end some 30 or 40 km high and the other end fixed to the ground.
It was an alternative proposal to the ISS, with a cost estimate of 20 Bn $ for the whole project. It may look more sci-fi like compared to the ISS but I wish this project had gotten the money instead of it. We wouldn't be worse off today, even if it would have turned out to be a complete disaster.
If you want to calculate length of track for various acceleration, its simple the formula is
length=0.5*velocity^2/acceleration
just simple 8-graders physics after all :;):
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With 1G being 9.8 meters per second per second (m/s^2)
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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You are looking at a track about 1500km long for a nice, gentle 2G acceleration all the way up to orbital velocity. 130G is not acceptable for any payload except bulk moon rocks, even a satelite would be crushed by its own mass like an egg run over by a battle tank.
The whole point of the magnetic catapult is not to get you all the way to orbit, nor is it to get you above whatever small air friction penalty, the whole point is to avoid the need for a big rocket first stage. The huge Saturn-V first stage, the most powerful rocket ever built by man and contributing most of the cost to the $2-3Bn rocket, only contributed 30% of the total Delta-V and ~60km of altitude.
This is what the catapult is for, to eliminate the need for a huge high-thrust first stage or the huge thrust needed to get a fully fueled spaceplane off the runway. Such a catapult coupled with a Scramjet engine would be ideal, since a spaceplane otherwise has to lug along heavy engines and fuel to accelerate to get off the ground and up to supersonic speeds to activate this marvelous engine.
Edit: Or, at the very least, up to Ramjet speed for a ramjet/rocket combo spaceplane.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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GCNR: (Gasp) Are you ready to reconsider strato-volcano eg. Kilimanjaro mag-lev lanches now? I hope so.
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No, I still think that a spaceplane that launches from a conventional runway is better then a magnetic catapult, but launching a spaceplane would be what such a catapult would be best at rather then flinging conventional rockets down the track.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Well, of course--I'm in favour of the "Burt Rutan approach," remember: Call it a returnable spaceplane, with or without a flyback first stage, however launched. But ... the railway switchyard-like scheme at the base of the mountain, with the mag-lev "first stage" sled returning down the track while generating power, after launching the rocket/obiter stage, to be replaced almost immediately with another rocket-bearing sled accelerating up the track, etc, etc--for pure utility, it's an idea hard to put aside.
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Utility? I wouldn't use that term persay... one of the biggest problems with a spaceplane is that first mach number, that getting off the ground and up to speed takes alot of wing and engine. This is more important than it seems because the mass margins for a spaceplane are pretty tight, and every pound you don't have to carry is a big deal.
However, such a contraption would be pretty difficult, combined with the difficulty of getting your spaceplane back and that the system isn't scaleable nor can economically support a low-ish (like 100-200 flights/year) flight rate... and that is a fairly strong case for a regular runway spaceplane.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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A maglev/railgun type system might work well combined with a carbon-nanotube cable space elevator and could be used to move cars up the cable all the way to geosynchronous earth orbit. It would be much faster than a climber that gripped the cable and would also have no friction with the cable. Of course building this long a cable and putting super-conductors or coils all along its length might be much more harder, expensive, and generally futuristic than the magnetic catapult with scramjet approach. I would consider both worthy projects with much more payoff likely than anything from the vehicles they're designing now (CEV, klipper, etc.).
No, I still think that a spaceplane that launches from a conventional runway is better then a magnetic catapult
I thought you made a very good case for the catapult. What advantage would a runway have? Your statements about the need to get a scramjet up to speed seem to imply that the catapult would be the best option.
You are looking at a track about 1500km long for a nice, gentle 2G acceleration all the way up to orbital velocity.
A track this long would not actually have to be built in order to accelerate the payload to the appropriate velocity. Rather a circular track could be used with the payload running around it many times before being sent off on a steeply upward slanting side track to launch it. This would be a kind of macro-scale version of what is done in particle accelerators to accelerate particles, although the velocities achievable would of course be much less.
Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.
-The Hitchhiker's Guide to the Galaxy
by Douglas Adams
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From a pure engineering standpoint, yes a maglev + ram/scramjet vehicle would be more efficent then a conventional runway takeoff, but the vehicles' efficency isn't the only measure of the system.
Economically, a big problem is flight rate, that building such a system would be very expensive and so would need a sufficent amount of business to justify it... a chicken and egg problem, given the very large amount of capital you would have to invest. If you only need a hundred flights a year or something, then launching from a runway makes more sense even if it requires a bigger vehicle. Such a setup only makes sense if you need very large launch capacity, and by the time that we need that kind of lift then the conventional runway-born space launch "fleet" will already be well established.
Being able to launch from anywhere in the world, rather then just from a single facility, would be awfully nice too I bet.
Trip time up a space elevator cable is not the problem so long as you can have two elevator car rails operating simultainiously up and down. The weight of a maglev rail up its length would be very prohibitive, it has enough trouble just supporting its own weight of a 36,000km cable.
A circular track to get you up to orbital velocity? A novel idea, but you run into the problem of having to keep a multi-tonne ship traveling tens of thousands of kilometers an hour from touch the side of the track due to centrifugal force, which would prevent magnetic levitation. The force on the payload (like the crew...) would be extreme if the track is anything less than an insane size. It would be easier just to build the linear one.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Going all the way to orbital at ground level will not work anyway, because of air friction. 2-3km/sec would already be a big help, but maybe air friction is too much even for that speed.
How much of an issue initial investment is, I don't know. But if that number of 20 Bn is anyhow close to reality, even for such a shorter track, it should bring in the price in a short time, if it can launch spacecraft with let's say 100 tonne start mass (reusable, payload 10 tonnes or even bigger, take off speed 3km/sec). You also don't need large wings if you get it up to this speed and point the part of the track, where it takes off, at an angle.
Maintaining all the superconductive equipment might be a problem though.
By the way, you will have to deccelerate the launching "1st stage" after the spaceplane has taken off, but it can be done with much higher G-load and it returns most of the energy from accelerating the 1st stage.
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Why do you need a first stage for launching? You could just make the space plane a one-stage vehicle with both the scramjet engine and the equipment to use the railgun/magnetic catapult launcher. It would probably add a little weight, but the gear for attaching to and separating from a second stage adds weight and, more importantly, complexity. A single stage vehicle would be fully reusable, able to be quickly prepared for relaunching, and would eliminate the problem of landing and recovering an unmanned stage.
Going all the way to orbital at ground level will not work anyway, because of air friction. 2-3km/sec would already be a big help, but maybe air friction is too much even for that speed.
You don't need to go orbital speed at ground level, hence the scramjet. You just need to get up to high supersonic speeds at which the scramjet will work well. A difficult and expensive, but theoretically possible way to deal with air friction would be to accelerate along a completely enclosed track kept under very low, near vacuum pressure.
Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.
-The Hitchhiker's Guide to the Galaxy
by Douglas Adams
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No, no, you misunderstood me. That first stage I was referring to was just a wagon gliding along the railgun track, it doesn't leave it at all. The single stage space plane takes off when it separates from this wagon. (maybe you don't need it at all, but it saves some weight on the plane)
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Sorry, I thought you were talking about a first stage that flew. What you're actually talking about makes sense, though. I'm not sure that the sled would be necessary, but I doubt it would hurt much. Probably either way could work fiine.
Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.
-The Hitchhiker's Guide to the Galaxy
by Douglas Adams
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A sled is a good idea. You can build it to be very strong without having to make it super-ultra-light weight like the space plane.
I think it is unlikly but possible you could get a sled-launched spaceplane all the way up to Scramjet ignition speeds, you really need to be hitting pretty high mach numbers for that, but it would be more than fast enough for a ramjet engine.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Was just thinking about the advantage of combining a maglev and a rotating space tether.
You could have one sort of vehicle launched from the maglev going up to orbital speed, then docking to the tether at the center (of rotation), going to the tip grappled to the electrical wagon, then released at 4 to 5 km/sec at the lowest point. No tricky cable catching for these and each deorbit would raise the stations altitude and reduce required heat shielding.
The other sort of vehicle would still go by "tip catching", but this would eliminate the need for re-boosting the tether.
It's only efficient when maglev and tether are used for roughly the same inclination though.
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There's a neat example of what you are talking about in the Anime Bubble Gum Crisis 2060 (or something like that).
I'm still skepticle as to if it would work, but it's cool to sometimes see your ideas in action.
He who refuses to do arithmetic is doomed to talk nonsense.
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Hmm found some anime called "Bubble gum crisis 2040" on first try. Will have to get and watch it when I have some time.
So now I'm having the same ideas as anime artists. What next? Rocket jetpacks? ???
:laugh:
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Putting one's life on the line, relying on a maglev launch to sync with a rotating tether?
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Nope, if you launch with the maglev you go directly for orbital speed. Then you slowly approach the center of the tether (center of rotation, that point is also moving at orbital speed) and dock to it similarly as you would do it with the ISS. Then you get the spacecraft attached to a climber wagon that gets it out to the tip and release it (when tip is moving slowest relative to Earth).
No need to sync tether rotation and maglev launch (although you need less time for approach if you launch when the tether passes overhead, but regardless of its orientation at that time).
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That's a relief: Development of a maglev "1st stage" retrievable booster-sled, plus rocket propelled 2nd stage payload (with or without propulsion core) to LEO, is what's contemplated first? An orbital platform would be assembled from payload elements resulting from multiple launchings. Then the flailing tethers would be added to the space platform. Now, I would like you to discuss your ideas regarding the configuration of the of the platform anchored tether arrangement and utilization for obtaining vehicular Earth escape velocity vectoring.
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Let me first describe what elements a fully developed tether would be composed of.
First there is a large space station at one end of the tether. Its functions are to be
a ballast,
a control center for the rest of the tether,
be living quarters for astronauts,
be the maintenance workshop for the tether
and later on a construction facility for larger space vessels
(only thinking about final montage of Earth produced parts for the time being).
This is made possible by its position at the end of the rotating tether, that would ensure high quality artificial gravity for the whole station.
The second part is at the center of rotation of the tether (Actually position of the center will change when the station is expanded or a spacecraft is moved along the tether or released or catched at the tip. But this change will be so minuscule as to allow this central module to reposition itself with relatively small electrical motors attached to the tether when required).
The purpose of this module is to provide a micro-g environment for
a power source like solar cells,
the docking module for orbital spacecraft (maglev launched craft would dock here for example),
eventually 0g materials production
or even some 0g hotel for tourists.
It would also be the home of a high power winch capable of pulling in and releasing back out the tether. (there is the possibility to change the energy/impulse of the rotation (i. e. increase/decrease the relative tip speed, by "gravitational pumping", an effect made possible by the gravitational gradient of the Earth that will make the tether turn fastest at vertical position and slowest at horizontal. So if you winch in the tether against high force (fastest rotation), then release it back out against weaker force (slowest rotation), you will increase the rate of rotation, or do it the other way round and decrease it without the need of any thrusters).
The third part is the other end of the tether that is very low mass compared to the station at the other end. This is the place that rotates at up to 3 to 4km/sec (doable with high strength materials that are on the market today) relative to the center. If the center is up in a 500-600km orbit (depends on length of tether) this means it is moving at approximately 7.5km/sec relative to Earth surface.
So the tip will move at 3.5 to 4.5km/sec rel. to Earth surface at the lowest point and at 10.5 to 11.5km/sec at highest point of rotation.
This part can be equipped with a grapple mechanism that allows it to capture a small tether deployed by suborbital craft moving at these speeds of 3.5 to 4.5km/sec.
Now the beauty of this concept is when you dock something in the center at orbital speed, then get it out to the tip and release it at the slowest speed you get the orbital energy, that would otherwise be wasted in heating up the reentry craft, to increase the tether's orbit.
Then you can use this boost to catch suborbital vehicles and get them to the center, that means to orbital speed, or get orbital craft to sling shot higher elliptical orits or even to Moon or Mars by releasing them from the tip at the highest speed.
Of course it might sometimes be neccesary to boost the orbit without docking any craft. For this case for example parts of the tether can be used electrodynamically to get the boost through interaction with the earth magnetic field. But any other high ISP engines are also possible options.
I will work out a more detailed concept when the simulation for the tether movement I'm developing currently will be completed.
//-----------------------------------------------------------
Well I don't know much about what initial investment would be needed to build a maglev capable of 2-3km/sec, but if it can be done cheaply enough it would make the tether much easier to build, too.
Let's have a look at both options.
1. Option
Maglev is completed first, cabable of launching multi-ton payloads into earth orbit (more likely with an additional rocket engine for the reusable "2nd stage", actually an SSTO with said 2-3km/sec take off speed).
You would either need a spaceplane capable of dealing with a full LEO reentry or one or two HLLV launches to get the core tether running and be able to receive/release multi-ton space planes at high relative tip speeds. Then you would have the ability to boost the station by releasing objects from the tip at low speed and with that being able to expand the facility or launch payload to Moon or even Mars trajectories.
2. Option - No Maglev aviable
In this case you would have to build the station by first getting a core station into orbit (one medium or heavy launch, with medium it will take longer to build up the station as you start with only a few hundred kg payloads, or less relative speed for the tip).
It makes sense to build several different sized reusable suborbital space-planes to get the required cargo pieces for construction of the full tether up part by part. Later on thes could be used to get passengers up or deliver cargo and satellites or materials for 0g production or even parts of larger spaceships for final assembly at the station.
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