Science: Spacecraft: Propulsion
Vertical Spacecraft Accelerator   (+1, -3)  [vote for, against]
Like a particle accelerator, but vertical and for spacecraft.

Particle accelerators work using very strong magnets. They esentially have a magnet switching on, which pulls the particle forwards, then the first magnet switching off and the second switching on, so that the activated magnet is always one step ahead of the particle, pulling it faster and faster until it goes very fast.

Any object contains electrons and can be moved using magnetic fields (scientists have managed to lift a frog using magnet repulsion).

My idea is this: Set up a very tall vertical cylinder, which is lined with very strong magnets. To launch an object, you turn on the base magnet which levitates the object in the centre of the first magnet. You probably need to spin it for the necessary balance. You then press the big red button which activates the sequence of magnets. They switch on and off in sequence (like the particle accelerator above) until the object is well above escape velocity. Once it clears the cylinder it should be fast enough to leave Earth's gravity forever.

This would primarily be used for small things, perhaps spare parts for existing spacecraft, or just very small probes.

The benefit of this is that it could be used more than once, and it doesn't cost a huge amount of money in fuel etc.
-- dbmag9, Apr 07 2006

Space elevators http://www.halfbake...Space_3a_20Elevator
Potpourri! [bungston, Apr 10 2006]

Google "coilgun". What you have proposed is a large coilgun.
-- bungston, Apr 07 2006

What you have proposed is a spacecraft melter. Anything in the atmosphere at seven miles per second is going to burn like a meteor. If you are going to revive this old idea, you need to address tower construction with some originality. Oh, don't forget rates of acceleration versus tower height.
-- baconbrain, Apr 07 2006

I thought this was called a rail gun?
-- jhomrighaus, Apr 08 2006

Rail gun has two conductive rails running the length of the barrel. The projectile brushes both rails, completing the circuit.

A coil gun has donut shaped electomagnetic coils surrounding the barrel at interval. The projectile does not need to make any physical contact with the mechanism of the gun.

Go to wikipedia for good descriptions of each
-- Galbinus_Caeli, Apr 08 2006

Sorry everyone. I did try Googling it, but did not get very far due to not knowing what it is called.
-- dbmag9, Apr 08 2006

A few years back a friend and I did some calculations to see how fast we could get a projectile moving using a 4 foot coilgun. It wound up to be about 10 m/s - about the same speed gravity would accelerate the thing over the same distance. We decided to tilt the tube vertically and amuse ourselves by dropping the projectile through it.
-- bungston, Apr 08 2006

//Set up a very tall vertical cylinder// Also means that your spacecraft would be pushing up several tons of atmosphere. You'd need side vents or something, as well as some magic construction method to get a structure tall enough. There is a reason that these rail/coil gun ideas usually end up being horizontal during most of the acceleration phase, and then head up the side of some convenient mountain for the change to 'verticality'.
-- ConsulFlaminicus, Apr 09 2006

It occurs to me that this device, essentially as set out by [dbmag9], might be used as a space elevator - I believe we have done space elevators here before and I will try to find a link - but usually the discussion hinges around how to construct supertall towers, not how to move things up the tower once it is built.

You would want the magnets to be very,very light. Maybe graphite electromagnets? Or can someone think of a lighter magnet?
-- bungston, Apr 10 2006

random, halfbakery