Couldnt a Magnet be used to throw objects into orbit?

Inspired by the “Strongest Magnet” thread.

Well, could a magnet be used to do that?, supose you build a very strong electro magnet, then put another one on top so they repulse each other and activate both, could such a device be used to put objects in orbit?, would it be cheaper than the current chemical rocket method?.

It would be difficult to aim straight.

Research is being done, but don’t hold your breath. The typical launching device is a type of railgun.

There are lots of engineering problems to overcome.

Check out the magnetic catapult in Heinlein’s The Moon is a Harsh Mistress, for the classic science fiction treatment of this idea.

Although, as beowulff said, don’t hold your breath.

why?

The biggest issue is the acceleration.

The space shuttle acclerates for eight and a half minutes. Even if you use a rail gun, you’d have to accelerate your object to escape velocity in less than a second. The forces would be huge.

Why is a railgun needed?, wouldnt the crude device I mentioned work better?, I guess there is a limit to the force you can give to a magnet that prevents doing it?.

If you wanted to send people they’ll get squashed, but couldnt it be used to send heavy objects, like metal for space stations and so on, and use the shuttle to send delicate things (like computers and humans?)

Why? If you can build a railgun, you can presumably build a really long railgun and stretch out the acceleration period. An evacuated tube gun that projects into the atlantic for a few hundred miles has been theorized as a low cost launch system.

There’s a basic orbital mechanics problem that no has mentioned yet that makes this impossible.

You cannot launch an object into a sustainable orbit with a single impulse (as opposed to a continuous acceleration, like that supplied by a rocket), unless the object is already at orbital altitude.

The reason for this is that a single impulse (like a shell launched from a cannon), can, at best, only put an object into an orbit that intersects the launch point. So any object launched from a given point on the surface of the Earth is either going to hit the surface of the Earth at some other point, or at best, is going to make one orbit that terminates at the launch point.

So your hypothetical satellite is still going to need a chemical rocket, even if you did use a magnetic launch system.

It is possible to launch an object with a single impulse into an escape trajectory, but the velocity necessary to do this means that you would have problems with frictional heating with the atmosphere (i.e. the object burning up on the way up).

The force of magnets gets smaller as you get farther away. So if you’re just using one magnet to push and one magnet on the payload, you’re only pushing for a short distance.
Which isn’t much different from just loading the payload into a giant cannon or whatever. First, since you’re only pushing for a short time, you need to push really, really, really hard. Second, the payload is going to be smooshed (just like being shot out of a giant cannon).

A railgun is a little different: it’s a whole line of electromagnets, so the payload can be pushed a more gently by each magnet, and still get up more speed.

Yes, but the idea wasnt to accelerate it gently, just to give it a brute force kick so big that puts it in orbit in one go.

Ouch, so no go then, perhaps using the magnet as a “first stage”?

What would be the advantage?

I think you’re underestimating the constant* force of gravity while overestimating the impulse strength a magnet can provide.

*Constant as in “always present from launch to orbit”, not as in a constant value.

Sure, this could work. You set up a platform with a matrix of powerful magnets, aligned slightly to create a focal point, such that another magnet would be repelled upward from that point.

Then you attach a bunch of rockets to the platform… :stuck_out_tongue:

Just as a nitpick, this isn’t a rail gun, but a coil gun. In a rail gun, your projectile is always in contact with two rails, through which you run a current through the projectile, with a magnetic field perpendicular to the direction of current and the direction of motion.

Here’s a proposal for a magnetic launcher.

Also, it’s not quite the same, but I recall a proposal for using a large, lightweight superconducting cable ring to levitate cargo off the planet. If possible at all it would only work at the poles, though, since that’s where the Earth’s magnetic field lines go up.

These things are often known in futurism and science fiction as “mass drivers.”

One way around the problem that a single inpulse can’t put something into orbit is not to attempt to put the payload in orbit. Throw it into space and catch it on the first pass somehow. You’d want a truly reliable retrieval system, plus some sort of self-destruct device in case of a loose projectile.

A common use these are put to in speculation is to send the output of mines and factories on the Moon to a Lagrange point. The ‘bucket’ is magnetically kicked away from the lunar surface with a good deal more force than needed for lunar orbit, because the target is a point in space closer to Earth than to the Moon. The lovely elements of the Moon’s crust are then cheaply available to build stuff in space, which can then be put into other orbits or could then travel about the solar system.

Actually, Cyrano De Bergerac was possibly the first to suggest using magnets to fly to the moon. (He was joking, he knew how absurd the suggestion is)

Why would massive accellerations have to be damaging to electronics? What if you were to pack a component in non-conducting, non-compressible liquid, freeze it and then launch it with the magnets as a first stage and then have a rocket 2nd stage perfect the orbit. The liquid then melts/evaporates away.

And (hijack) whatever happened to the cable-system to heaven wherein cables are anchored to the earth and extend well into space? Centrifugal force keeps the cables rigidly erect (heh) and you get stuff into space via elevator.