Caterpillars

I can't help you with the Caterpillar drive (except to say that it is used successfully on bulldozers and tanks ;-)

As far as non-traditional means of propulsion, if you haven't come across them, you might be interested / want to read up on the following (I am almost assuredly not using the correct or best terms to use for a google search.)

• ion drives (which accelerate a spacecraft "continuously" by ejecting a continuous stream of (elementary) particles of some sort accelerated in some way (like by an electromagnetic field). If I'm not mistaken, some variations of these have actually been used on some long range space probes.
• the concept of launching and accelerating a space craft by (rapid) multiple nuclear explosions behind the spacecraft (even discussed (maybe in Pop. Mechanics type science fiction) for launch from earth--other times discussed (iirc) for launching from earth orbit
• solar sails (large sails that catch and reflect solar radiation to propel a craft)
• hmm, trying to remember/ think of a more accurate name--let me say linear accelerators--long sloped rail systems that use various technologies (electric linear motors, maybe even rail gun technology) to accelerate something from rest on earth to a speed to achieve earth orbit or even escape. (The last time I saw a discussion of such, there was also a discussion of something like tugs that would be needed in space to reposition the payloads after launch (on the assumption that you're sending parts up to assemble some larger craft or space station). (Sometimes (maybe usually) imagined as evacuated chambers (to reduce resistance) with special doors to allow egress of the payload at the end of the track without totally losing the vacuum.)
• the space elevator (maybe a slightly different category--maybe less a drive than a "positioner")
• wormholes (the latest research (/ speculation?) I've seen seems to indicate than wormholes might only be possible at a microscopic level, thus not really usable for anything macroscopic)
• hmm, if there really are branes, some means of moving in the bulk dimension from one brane to another, or, more generally
• assuming the multiple dimensions of various string theories, traveling in one of those other dimensions

For the last two, I'm not sure I've seen anyone speculate on those possibilities (except maybe very generally--traveling in (or to?) another dimension (credit the "Outer Limits")

If you are a physic, you should have a look on Bruckard (I think that this is the correct way to write the word) Heim Theory!

I tried some years ago, but my brain got fused and then I started to drink to cool it down!

cheers!

Thanks to Switchman and his link to Wikipedia: Magnetohydrodynamic drive, I now realize that the ion drive I mention in the first bullet is a type of magneto hydrodynamic drive.

it is not the same type. It is a similar idea. There is no 'Hydro' in the ion drive....

Good point, thanks--I guess I read a little more into the wikipedia article than it actually says--from the article:

"

Spacecraft propulsion

A number of experimental methods of spacecraft propulsion are based on magnetohydrodynamic principles. In these the working fluid is usually a plasma or a thin cloud of ions. Some of the techniques include various kinds of ion thruster, the magnetoplasmadynamic thruster, and the variable specific impulse magnetoplasma rocket.

"

(I had to read it again to see where I got confused--I guess it was the "based on magnetohydrodynamic principles"--sorry for the confusion.

Did you know that Science Fiction writers get their technology for their stories from places like JPL (Jet Propulsion Laboratories) They actually have a room set off for writers to sit and watch the experiments they do. Also, the example of the multiple nuclear explosions under a large iron plate to launch a craft into space was actually theorized for the space program and shelved for something better.

For anyone that isn't into reading Science Fiction, you can read a science fiction novel and the things that would seem far fetched to you as far as technology is concerned much of it has been actually theorized on paper by some physisist.

Many of those examples you mentioned I read in science fiction novels and it was one of the Science Fiction writers that wrote a book about where science fiction writers get their material. Larry Niven is the Auther and he and some other science fiction writers, write their stories and play off of one another and work together and a lot of joint stories to keep the stories coming out.

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

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

I believe that since sea water is a conductor, then the correct progression of the magnetic field to the rear will cause a flow of water to the rear. In essence a low velocity water jet with zero impact.

MHD water jet search

The fastest, most powerful drive in the universe is that composed of two legs attached to a working body and brain.

If each human being, working alone, or together with one, two, or a couple dozen other like-minded individuals, worked to produce food, shelter, clothing, tools and items for amusement, such as musical instruments, they could exist peaceably, and with great satisfaction, and never have the need to import or export anything!

Dedicating our country to God and the above reasons are why America enjoys the success and freedom that she does.

I forgot to mark this as off topic, sorry!

This one is interesting:

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

Not sure about the viability at this time. There are several authors who mention these motors, i.e. Clive Cussler. The main character of the story line is Juan Cabrillo I believe. This may get you in the ball park. He goes into depth discussing the motor, how it operates, and its capabilities. I think there is some reality to this but the actual usefulness is still several years out. If they did work as explained, it would be free energy for all ocean going ships. No fuel to carry, etc.