As I said before, Philip, gravity slingshots are rubbish, since the speed gained on approach must be lost again on recession. Neville. philip madsen <pma15027@xxxxxxxxxxxxxx> wrote: I'm sure that you are correct Neville. especially as The fields rapidly deploy, and redeploy as fast as is necessary (even light speed) to concentrate the union of their initially separate fields as they come together (a closed magnetic circuit) . As I said, an awfully complex bit of math.. like impossible.. I know that the moving magnet can be accelerated into through and out of the field without capture, but all of the input attraction as energy at the approach will be equally required to force the escape. There will be no gain of energy from the flyby.. Thus I was wondering just how energy can be taken by a satellite in the socalled slingshot flyby of Jupiter to propell it further from the Sun... That gravity and magnetism are different forces should not alter the basic premise that energy gained by a fall is recovered during the climb... or visa versa.. Philip. PS In case it was not noticed I am searching for the flaw in the smot linear motor demonstration I showed earlier.. --------------------------------- Yahoo! Mail is the world's favourite email. Don't settle for less, sign up for your freeaccount today.