There would be a differnence in gravity, and atmospheric conditions on Jupiter, your craft would already have to be moving at high velocity and then we would need an efficient nuclear fusion reactor that can fuse hydrogen with itself, which is a v difficult reaction to ignite without loss of energy. Any craft going near Jupiter faces it super gravity and its pressure NASA's Galileo did very good study before being crushed by the pressure of Jupiter, electronic components are thought to be vunerable to the strong Jovian radiation fields