@S1-A.ARPA,@MIT-MC.ARPA:JNC@MIT-XX.ARPA (06/11/85)
From: "J. Noel Chiappa" <JNC@MIT-XX.ARPA> "obsolete technology as ... space propulsion systems that move by throwing stuff out the back" Ahem. If you know of some way to move something that DOESN'T involve 'throwing something off the back' (including photons), please step up and collect your Nobel prize (not to mention one trillion stars from the Outsiders!). (I except using electro-magnetic repulsion/attraction drives; such things are possible now, albeit difficult. We have no way to create charge and no magnetic monopoles; dipoles generate little push in fields with little gradient. I would think that the main thing is that the E/M fields in space are too irregular to use as something to push against.) You're right; dragging up a lot of mass just to throw it off the back end is the Wrong Thing, but at the moment it's still the only thing.... Noel -------