On Thu, 28 Nov 2002, robert nelson wrote:

*>>*>In space there will be no matter to push against
*>>*>and it won't work. :o)
*>>
*>>I aggree.
*>>
*>>
*>SO WHAT DO THE ROCKET ENGINES  PUSH AGAINST?
*>HOW DO THEY WORK?

They throw out some mass at some speed so they generate some impulse. The
point being that at least one of the items involved (the vehicle or the
space) must have some mass that can be moved. A propellantless engine
either uses the medium it moves through (like a propeller or jet airplane)
or something else. The something else is the mystery in the op. Since NASA
has tested the device in a vacuum and found that there still is thrust.
They used ion detectors to make sure that whatever pushes the vehicle is
not ions.

Peter

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