I couldn't help but notice that in the Wikipedia entry for the Ares V it mentions that the Ares with an upper stage would be capable of launching something like the Cassini or Galileo probe without a gravitational slingshot. This entry is uncited and I don't know if it is accurate or not. Assuming for a minute it is then presumably if the Ares V were used in conjunction with a series of gravitational slingshots in the same manner as the Galileo or Cassini probes it'd be capable of delivering that much larger a payload to Jupiter or Saturn. I would guess that with a probe that size one could put the sensor package slated for the Jupiter Icy Moons Orbiter into a probe which carries a larger fraction of chemical fuel to maneuver around the Jovian system. Of course there'd still be the need to power the ice penetrating radar and high bandwidth communications system out around Jupiter, so the nuke would likely still have to go along for the ride. It does seem something of a waste to haul a nuclear reactor all the way out to Jupiter with conventional propellants when it could likely have supplied that energy. In any event I believe NASA scrapped the Prometheus program, so I guess for now it'd end up studded with a hundred or so RTGs to supply the radar.<br /><br />Just out of curiousity, is this a doable program? I would assume that at some point there will be an advance in space power supplies similar to that promised by Prometheus. Given that, might this idea work as a kind of Orion Applications Program for before or after the moon landing? I'm afraid the math is a bit beyond my ability and available time, but I guess my question boils down to whether the chemically powered probe would be able to perform the maneuvers NASA had planned for the ion drive powered JIMO while staying within the launch capabilities of an Ares V.