http://www.suncafe.us/News/article/sid=5067.html

88 millinewtons directional force from a sealed tube full of microwaves? and they are improving it, hopefully to the point they can lift up an aircar or spaceship to orbit

Means there is no emissions: IE the flame from a rocket or ions from an Ion engine.

sounds pretty damn good so long as it doesnt break and start cooking people

This is actually very very clever.  I cant imagine it ever making enough thrust to work on earth in the way the article author describes since it would need some amazing new developments in waveguides - but for space apps no wonder hes getting so much investment his way.

looks pretty cool to me

...even better when you chop one end off his microwave tube and use it as a microwave gun !

Very interesting, lets hope its one of these technologies that takes off (pun intended) especially after the success of the ion engine on SMART-1.  That table at the end says it all, for the same wattage, you get more output and for a lot longer, cant see anyone wouldnt want to take it up.

The big thing is you have no fuel to carry on your satelite/probe/spaceship and all the energy comes from the sun.

Present sats take with them a limited amount of fuel to allow them to keep on station and avoid drifting out of orbit, when that runs out you loose control of the sat. This will mean that unless there is a severe malfunction of the system the sat can keep itself on station until its solar pannels fail.

For probes and spaceships even the SMART 1 Ion propulsion system needs fuel, although its a lot less than a normal rocket. Present generation under development will hopefully provide ten times the thrust from the same fuel as   SMART 1 and the Us is testing NEXT which produces up to 236 milliNewtons of thrust but it will still needs to carry fuel. This thing doesnt need any.

If the development of this comes anywhere near expectations then it should provide enough thrust to take astronauts to Mars and back in a reasonable time without any problems.

http://www.newscientistspace.com/channel/space-tech/dn8599-superpowerful-new-ion-engine-revealed.html
http://www.newscientistspace.com/article/dn9616-new-ion-engine-could-propel-spacecraft-to-titan.html

thing is for satellites in high orbit, how much thrust do you need ?

it its just keeping itself in the right position/orbit, then I guess its no biggie if it takes a while to adjust itself

then again with nu fuel and what I guess would be a more accurate/scalable propulsion system it could keep better track of its position

It takes weeks for a sat to go out of orbit so only a little adjustment is needed and it can take place over a long time. In low orbit it would keep the thing from fully re-entering the atmosphere so for spysats it will be a godsend if they get it working to any real efficiency.