# Maglev ISS Earth Moon Mars Transport

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#### therocketjohn

##### Guest
Could a giant Maglev launcher be created to orbit the Earth, while waiting for specially designed space craft to be loaded, then launched to the Moon or Mars via proper aiming and Maglev technology? How fast could the Maglev launcher shoot a space ship into space, and how long would it take to get to the Moon and to Mars at that speed? It seems that if we had a launcher orbiting the Earth, Moon, and Mars and it worked, then that could be a way to make sustainable deep space transportation while not depending on any one fuel source. Also, I wonder what the power requirements of the launcher satellite would be?

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#### RS_Russell

##### Guest
I don’t think I can give you an answer about trips beyond Earth orbit, but from what I've read in the near term any railgun would only be able to send small payloads into space.

The biggest obstacles would be the needed power to run your maglev as well as the heat that these satellites would have to endure at launch. Also, launch forces due to acceleration might be quite high, requiring specially reinforced electronic packages.

The Navy has experimented with a railgun and I believe that system can develop speeds up to 6 km/sec for small projectiles. That’s close to the required orbital velocity of 8 to 10 km/s. Yet even a satellite with an optimal aerodynamic fairing (picture a highly streamlined Explorer 1 from the 1960s for relative size and shape) would experience velocity losses due to friction, drag, and gravity. That loss can add up to almost 3 km/s. So, the total velocity to get into LEO required b y your satellite is between 11 to 13 km/s, I believe.

Your maglev launch system would likely look a lot like the launcher in “When Worlds Collide,” where it goes up the side of a mountain. Only instead of riding on a track the satellite would blast through a ringed tunnel. Those rings are electromagnets and they alternately grab and propel your sat toward the exit on the launcher. These have to be powered b y capacitors that can hold something on the order of 36 M-Joule. That’s huge! The power required would be on the order of 2 G-Watts. The acceleration on this system is about 10000 times the force of gravity, however despite losses a small 1-kg payload could reach over 100 km about 2 minutes. It's speed would be roughly Mach 6, which is maybe a quarter of the Mach 25 something in orbit flies at. That Mach 6 sounds good, but this would be a sub-orbital flight. The package would follow a ballistic arch and after some time would drop back to earth. Sort of like a sounding rocket.

To go higher and achieve orbit in the near term, your maglev concept might be used to launch a sat but the sat would carry a rocket motor which could give it enough thrust to achieve orbit. This could be used for cube-sats and small payloads under maybe 5-kg. I know that sounds disappointing to use a rocket with your maglev system however the current state of the art might require it until something more powerful is developed. Pewrhaps if the railgun was carried via balloon or plane that might work, although again, the power requirements are pretty stringent. The Navy tests were promising, but I think they only made a few test shots. To have an effective launcher you will need to be able to do this repeatedly with little down time in between.

RSR

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#### MeteorWayne

##### Guest
RSR, I think you missed his point. The suggestion was for a Maglev system in orbit. To be used as a device to propel objects out of LEO to interplanetary (or maybe interstellar) paths.

Rockets would still be required to get to LEO, but the fricion and drag would not be an issue, and the required acceleration might not need to be excessive.

Of course, the infrastucture would be huge, but it's an interesting idea I've never heard of before.

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#### Mee_n_Mac

##### Guest
MeteorWayne":31wsoxfi said:
RSR, I think you missed his point. The suggestion was for a Maglev system in orbit. To be used as a device to propel objects out of LEO to interplanetary (or maybe interstellar) paths.

Rockets would still be required to get to LEO, but the fricion and drag would not be an issue, and the required acceleration might not need to be excessive.

Of course, the infrastucture would be huge, but it's an interesting idea I've never heard of before.
Just musing a bit ..... how does the theoretical Maglev launcher (ML) remain in place after each launch ? Naturally each launch will slightly push the ML out of position and so some amount of fuel will have to be used to maintain station. I guess the advantage would be that the mass of the payload would be smaller since it need not have rockets nor tanks nor fuel etc, etc so the overall mass expelled would be smaller and so less fuel would be needed to maintain station. Then again you'd have to aim the ML for each launch which might mean more fuel than a conventional launch, especially if the ML is massive. Interesting idea.

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#### RS_Russell

##### Guest
No, I understood the point, I just don't have a useful answer to his question . I suppose such a system could eventually be built but you would need something with a large mass to place the maglev on or some sort of thruster system. The mass or the thrusters would compensate for whenever you lobbed a payload at Mars or the Moon the space-maglev might go in the opposite direction. Also, larger payloads or manned payloads might be problematic. The accelerations for such a system might damage cargo or be deadly to humans. In the near term there are likely better ways to go.

O'Neill did some great stuff on the use of railguns to steer asteroids as well as slingshots (mass-drivers) to put material mined on the Moon into orbit to construct space colonies. However these payloads were on the order of kilograms. Also, there have been studies done for orbital particle accelerators, where anything above 100 TeV might be best off being constructed in space, due to energy availability (solar) and cryogenic cooling.

Oh, one other thing: if we are going to invest resources someday into these sorts of systems a better concept might be something like the magsail. This sail would have used a magnetic field to deflect charged solar particles. This would have transferred momentum and accelerated the magship. It is a pretty cool idea although the accelerations are not as dramatic as those of a railgun.
RSR

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#### kelvinzero

##### Guest
Mee_n_Mac":7if3kaez said:
MeteorWayne":7if3kaez said:
RSR, I think you missed his point. The suggestion was for a Maglev system in orbit. To be used as a device to propel objects out of LEO to interplanetary (or maybe interstellar) paths.

Rockets would still be required to get to LEO, but the fricion and drag would not be an issue, and the required acceleration might not need to be excessive.

Of course, the infrastucture would be huge, but it's an interesting idea I've never heard of before.
Just musing a bit ..... how does the theoretical Maglev launcher (ML) remain in place after each launch ? Naturally each launch will slightly push the ML out of position and so some amount of fuel will have to be used to maintain station. I guess the advantage would be that the mass of the payload would be smaller since it need not have rockets nor tanks nor fuel etc, etc so the overall mass expelled would be smaller and so less fuel would be needed to maintain station. Then again you'd have to aim the ML for each launch which might mean more fuel than a conventional launch, especially if the ML is massive. Interesting idea.
One way it could stay in orbit is by decelerating returning objects. Firstly down to the velocity of the maglev, and then down to suborbital velocity for a more gentle return to earth.

I have always liked the idea of an orbital ring

http://en.wikipedia.org/wiki/Orbital_ring

But the way I imagine it, it would just be a string of unconnected satellites spaced say ten meters, each giving a tiny boost, and there would be no 100km tether down to earth. You have to fly up on a suborbital flight to catch this overhead monorail thing. It keeps the riffraff out.

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#### neilsox

##### Guest
My guess is we cannot build a useful maglev system at the ISS with today's technology even for 1000 billion dollars. Worse large and medium maglev on Earth's surface have a top speed of about 300 miles per hour which is puny compared to the delta v needed to get to the Moon or Mars. In 30 years we may have maglev at 5000 miles per hour in LEO = low Earth orbit. I think this would get us to the moon in about 100 hours = 4 days. About half of the delta v would be used to climb the rest of the way out of Earth's gravity well. Also there is a recoil problem. The ISS is accelerated by about 50 miles per hour (astronauts wear your seat belts) if the mass accelerated to 5000 miles per hour has 1% of the total mass of the ISS. The ISS would have to be reinforced to survive the stress, and would be in a new (not necessarily better) orbit. Also we would still need rockets to get in a circular orbit around the moon or to make a soft landing on the moon or Mars. Neil

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#### therocketjohn

##### Guest
It sounds like there are two major hurdles:

1)How does the launcher stay in orbit instead of getting pushed back to earth during each launch?
2)Are the power requirements feasible?

For #1, one solution might be to only let launches occur when the LEO maglev launch orbiter is at the point in orbit where the counter forces from the launch push the orbiter in an orbital path rather than towards the Earth. Then, perhaps it could be setup in a way in where the launcher orbit reverses during each launch so that the launcher orbital velocity helps aid the launch trajectory while not creating requirements to continuously slow the launcher back down.

For #2 it sounds like the capacitor power requirements are pretty huge. 36M joules was referenced. I searched for "worlds biggest capacitor" and found a 50M joule capacitor bank in Germany that ran around \$10million + about \$25 million to build, which seems like nothing compared to a NASA program. That doesn't include getting the thing into orbit, but from the picture at http://www.space.com/common/forums/posting.php?mode=reply&f=13&t=18159, this seems smaller than the ISS, so maybe it is doable with the new Aries Heavy Launch capabilities.

I'm an optimist, but the costs, scale, and technology requirements don't seem that far out to me. Whether the thing would get powered via solar panels or fuels from earth launched payloads, I don't know. Also, I wonder what types of accelerations human can take when in the gravity of LEO? For some reason, I have thought that humans can take more acceleration if less gravity is present, but I have never seen this quantified.

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#### neilsox

##### Guest
Hi rocketjohn: Your thoughts seem correct. 1 The orbit of the launcher does change as you suggest, but not by much if the launcher is 100 times, or so more massive than the mass accelerated.
2 Since chemical rockets are not very efficient, likely the maglev launcher uses less energy to accelerate a pay load, but it is still a lot of energy, so will be challenging.
I agree, careful timing of the launch can move the launcher to a higher altitude instead of an altitude dangerously close to re-entry into Earth's atmosphere.
If the average maglev acceleration is 10g = bad on humans = 322 feet per second per second: S = 1/2 at squared = 161 times 4 = 644 feet of maglev track needed. Since the acceleration only lasts 2 seconds, most humans will survive. v = at = 322 times 2 = 644 feet per second = 439 miles per hour = not enough delta v to reach high Earth orbit and beyond, so the maglev track needs to be longer than 644 feet to be useful. Miles long to get to Mars in 4 months. Neil

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#### therocketjohn

##### Guest
neilsox":ewjuuzr7 said:
Hi rocketjohn: Your thoughts seem correct. 1 The orbit of the launcher does change as you suggest, but not by much if the launcher is 100 times, or so more massive than the mass accelerated.
2 Since chemical rockets are not very efficient, likely the maglev launcher uses less energy to accelerate a pay load, but it is still a lot of energy, so will be challenging.
I agree, careful timing of the launch can move the launcher to a higher altitude instead of an altitude dangerously close to re-entry into Earth's atmosphere.
If the average maglev acceleration is 10g = bad on humans = 322 feet per second per second: S = 1/2 at squared = 161 times 4 = 644 feet of maglev track needed. Since the acceleration only lasts 2 seconds, most humans will survive. v = at = 322 times 2 = 644 feet per second = 439 miles per hour = not enough delta v to reach high Earth orbit and beyond, so the maglev track needs to be longer than 644 feet to be useful. Miles long to get to Mars in 4 months. Neil
Can humans take more acceleration if it is higher in orbit? I'm thinking the acceleration humans can take is the reason the track has to be so long. I imagine the electronics and components available today could accelerate a space ship much faster if humans could take it. Also, does the track have to be rings, or could it just be kind of like a roller coaster track? If it were rings, that seems like it would limit the size of space crafts that could be loaded because we can only launch rings that are so big. I'm thinking a track setup might be better so that we don't have to construct giant rings in space and because of low gravity at those altitudes. I'm thinking that even little tracks could launch large craft as long as the they can handle the current/ power requirements for the maglev.

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#### JeffreyNYA

##### Guest
My Vision of this is a little different. What I was think was instead of having a massive infrastructure in one place in orbit, but smaller independant accelerators between the starting point and destination.

Basically there woud 2 half moon shaped accelerators that a ship would pass through. The accelerators would magnetically pull the ship through the opening and would push them out through the other side. The Accelerators would need to be well powered for this and for positioning. Nuclear and Solar would be needed with Ion engines to change there location.

This design would create a highway of sorts between locations. They would be moveable to keep in alignment with the orbits. The accelerators would be able to slow down the ships as they get closer to there destination.

The only issues is how do you change the polarity of the ship to be pulled through and then to accelerated out? This solution would make it possible for a ship to have little fuel onboard. just enough for manuvering in orbits and getting to and from the "highway"

Since I am not an expert in any of this, and its only an image in my head I have no idea how to technically acheive this.

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#### crazyeddie

##### Guest
JeffreyNYA":1tl1crt7 said:
My Vision of this is a little different. What I was think was instead of having a massive infrastructure in one place in orbit, but smaller independant accelerators between the starting point and destination.

Basically there woud 2 half moon shaped accelerators that a ship would pass through. The accelerators would magnetically pull the ship through the opening and would push them out through the other side. The Accelerators would need to be well powered for this and for positioning. Nuclear and Solar would be needed with Ion engines to change there location.

This design would create a highway of sorts between locations. They would be moveable to keep in alignment with the orbits. The accelerators would be able to slow down the ships as they get closer to there destination.

The only issues is how do you change the polarity of the ship to be pulled through and then to accelerated out? This solution would make it possible for a ship to have little fuel onboard. just enough for manuvering in orbits and getting to and from the "highway"

Since I am not an expert in any of this, and its only an image in my head I have no idea how to technically acheive this.
It's an interesting idea. Larry Niven used this concept in his novel Ringworld. The rim of his Ringworld had a series of magnetic launchers and decelerators projecting out from a platform. Outgoing ships would be accelerated; incoming ships would be decelerated with the same mechanism. But the Ringworld was huge, and the accelerator/decelerator rings stretched out over hundreds, if not thousands, of miles, in order to keep the G-forces within human tolerances. I'm not sure anything we could build in orbit would work.

Easier and more practical (once we develop carbon nanotube cables) to build a Space Elevator, which works to launch vessels into interplanetary trajectories with a slingshot effect as well as hoisting them into orbit.

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#### JeffreyNYA

##### Guest
crazyeddie":3aeirgzh said:
JeffreyNYA":3aeirgzh said:
My Vision of this is a little different. What I was think was instead of having a massive infrastructure in one place in orbit, but smaller independant accelerators between the starting point and destination.

Basically there woud 2 half moon shaped accelerators that a ship would pass through. The accelerators would magnetically pull the ship through the opening and would push them out through the other side. The Accelerators would need to be well powered for this and for positioning. Nuclear and Solar would be needed with Ion engines to change there location.

This design would create a highway of sorts between locations. They would be moveable to keep in alignment with the orbits. The accelerators would be able to slow down the ships as they get closer to there destination.

The only issues is how do you change the polarity of the ship to be pulled through and then to accelerated out? This solution would make it possible for a ship to have little fuel onboard. just enough for manuvering in orbits and getting to and from the "highway"

Since I am not an expert in any of this, and its only an image in my head I have no idea how to technically acheive this.
It's an interesting idea. Larry Niven used this concept in his novel Ringworld. The rim of his Ringworld had a series of magnetic launchers and decelerators projecting out from a platform. Outgoing ships would be accelerated; incoming ships would be decelerated with the same mechanism. But the Ringworld was huge, and the accelerator/decelerator rings stretched out over hundreds, if not thousands, of miles, in order to keep the G-forces within human tolerances. I'm not sure anything we could build in orbit would work.

Easier and more practical (once we develop carbon nanotube cables) to build a Space Elevator, which works to launch vessels into interplanetary trajectories with a slingshot effect as well as hoisting them into orbit.

The only thing different about what I am taking about is the fact that there would only be a couple just outside of earth orbit to help get the ship moving. The others would be designed to sit a certian locations along the way to say mars. Think of it more as a tunnel that you can't see.

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#### kelvinzero

##### Guest
The problem with several on the way to mars is that they would seldom be aligned usefully, and if they were aligned then a craft passing though them would nudge them out.

I think the best place is tied down in one place such as earth orbit or the moon. In earth orbit you need both incoming and outgoing craft to maintain its momentum but the moon could eventually be a great place for launching and landing interplanetary cargos with a maglev around its entire circumference

I still like the orbital ring concept but we would probably have to have a moon industry running before we would consider that.

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#### therocketjohn

##### Guest
If a space elevator lifted a craft into geosynchronous orbit, how fast is that orbit at what ideal altitude above earth? Perhaps that orbital velocity can be used to sling the craft to the Moon where it loads into the Maglev Moon Orbital Launcher that gets you to Mars or else ware. You don't even have to land on the Moon unless you want to stop for McDonalds.

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#### MeteorWayne

##### Guest
At Geosynchronous orbit( ! 36,000 km) , the velocity is 3073 m/s, or 11063 km/h, or 6872 mph.

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##### Guest
I suppose it would be less useful in some ways because you have to get there first, but what about building it on the surface of the moon? A lack of atmosphere and plenty of cheap and uninterrupted real estate might prove useful?

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#### neilsox

##### Guest
Acceleration rings would work poorly, as most of the acceleration would occur in a millisecond or less. Acceleration tunnels or tracks would spread out the acceleration over about one second, which is better. Free flying balloons could support the tracks in Earth's atmosphere, at about 100,000 feet altitude. Mostly the tracks need to be orbiting at altitudes of 300 miles to lots more.
Human tolerance to 10g is typically worse starting at or near zero g.
If we have an average of one million space craft en-route about the inner solar system, then perhaps random accelerating tracks are practical.
We would give the computer a range of departure times, latest acceptable arrival time, name of the destination and starting point (sort of like Mapquest) Maximum g permissible. The computer would calculate the best utilization of a few out of a million or more accelerating tracks. Nearly all of them would be in the wrong place at the wrong time and/or heading in the wrong direction at a speed too fast to be used safely. Collision would all but surely, be a disaster for both the track and the space craft. We would generally adjust the track/tunnel orbit, only if a collision with an asteroid, comet or planet was likely soon, except for minor adjustments just before accelerating a space craft. The orbit of the track is changed radically (recoil) if the accelerated space craft has more mass than the track/tunnel, but mostly that doesn't matter as the rail/track is still in solar orbit, and the computer can use the new orbit to accelerate different space craft.
The above suggests that stationary (with respect to what?) is rarely practical even at L1, L2, L3, L4, L5 or L6 since the track is accelerated as well as the spacecraft. Neil

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#### Jason_Jay_Dan

##### Guest
In my mind I see rings like the ones on stargate or Babylon 5 that a payload passes through...as it does it gathers speed until it reaches escape velocity and is sent on its merry way. For station keeping you might be able to use some sort of solar or electromagnetic sail. I'm not sure you would want to use this for human transport but, like mentioned if it were long enough may be. This set up could be used to help facilitate the in orbit manufacturing of larger spacestations and human habitats not to mention ships. Robots could mine the Asteroid belt and use a magnetic launcher to send materials back to Earth orbit where they would be used to construct the stations. Wikipedia made mention of placing a magnetic launcher on the moon where there would be no atmospheric friction and there are plentiful sources of sunlight for energy. The moon launcher could also be used to send useful manufacturing and otherwise payloads back to Earth orbit. Something that caught my attention while perusing wikipedia one day was that it may be possible for a craft that can generate a large/powerful enough electromagnetic field to reach orbit directly from the Earth's surface from the pole's. If you could do that and use a magnetic launcher just think how that could open up the entire Solar System to us. I believe that this plan will soon be feasable...if we are steadfast and do the requisite reasearch and testing which is never a guarantee.

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