"In order to launch a space probe out of the solar system, it is decided to send it close to Jupiter. Why does this reduce the amount of fuel needed?"
The Attempt at a Solution
I can't think of anything at all. I am trying to think in terms of it gaining kinetic energy, but because gravitational fields are conservative, it seems to me that however you choose to approach another planet and whatever planet it approaches, the probe will gain a certain amount of kinetic energy approaching the planet but lose the exact same amount leaving the planet? Perhaps it could be something to do with rotation of Jupiter?
Thanks in advance :)