Boys go to jupiter's inner most moon io and are systematically killed by either jupiter's immense radiation or by volcanic blasts many times bigger than the ones seen on earth not to mention the fact that the spacecraft used could land in one of thousands of volcanos the biggest problem however would most likely be logistics if you the space craft is not destroyed in the asteroid belt you still have a very big distance to cover and any number of things could go wrong and on the final approach you could get sucked into jupiter it self