[SunkenCiv]

I wasn't suggesting a landing on the gas giants (which probably don't have a solid surface per se), just their moon systems. Since a signal can be received from within Jupiter's magnetosphere, there shouldn't be any problem shielding a crew, but the difficulty (mostly toting the fuel) remains. Io at least probably can't be landed on.

[spacecowboynj]

Io is so close to Jupiter that the size facing the gas giant bulges 60 feet into the sky. It's the most actively volcanic body in the solar system and is literally hell on earth. There is a huge deadly cloud of ionized particles surrounding the little moon due to the particles it's volcanoes are shooting up that are getting charged by Jupiter's magnetosphere. Where radio signals can be sent and/or received is no determining factor as to human survival. There are many scientists today who think that human interplanetary travel just outside the Earth's magnetosphere is an impossibility because of charged particles from the sun. Shielding won't help because the particles pass through solids no problem. NASA did an exhaustive study of the hazards that can be found here:

http://www.space.com/scienceastronomy/generalscience/space_health_011205-1.html

And forget the radiation, just the loss of muscle mass and bone is a huge hazard to long term space travel. Exercise and a rotating g-chamber (as per 2001: A Space Odyssey) will not help you. Astronauts on a routine mission to the ISS lose 30 percent of their bone structure due to the lack of gravity. And you cannot simulate gravity waves. Scientist even doubt that a colony can be put on the Moon due to the onset of bone loss and the exposure to radiation. Mars may be out of the question because it has no magnetosphere and thus is bathed in radiation. We'll have to rely on the robots for the heavy stuff.

[spacecowboynj]

We would probably be ok landing on every other one but Io but the trip alone would probably kill us. Our fastest spacecraft take, what six or seven years to get out there? And frankly, Jupiter's charged magnetosphere would probably kill us anyway. Let me put it bluntly: Jupiter's magnetosphere is the biggest thing in the solar system. The sun could easy fit inside it. And actually, I just researched it. Sadly, here's the deal:

The intense radiation field that surrounds Jupiter is fatal to humans. If astronauts were able to approach the planet as close as the Voyager 1 spacecraft did, they would receive a dose of 400,000 rads, or roughly 1,000 times the lethal dose for humans.

No Jupiter trip for humans. Not even the moons.