h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Since Jupiter has no solid surface, no human will ever walk on the planet. In fact, any attempt to visit the Jovian system will require heavy shielding. Jupiter's magnetic field captures electrically charged particles from the Sun and from the planet's volcanic moon Io. These particles create strong radiation belts. Around Io's orbit, the radiation belts are powerful enough to kill an unprotected human in a few minutes. That adds one more item to the list of Jupiter's superlatives: deadliest radiation belts.

http://stardate.org/resources/ssguide/jupiter.html

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The only protection from radiation is MASS. Mass doesn't travel well.

Europa will never be habitable for human kind because the ambient radiation is killer-magnitude.

QUOTE--But a new report in the Jan. 27 issue of the journal Nature concludes that Europa does indeed contain plenty of biological fuels, thanks to billions of charged particles that constantly rain down from neighboring Jupiter.

This relentless bombarbment of radiation "should produce organic and oxidant molecules sufficient to fuel a substantial Europan biosphere," writes Christopher Chyba, associate professor (research) of geological and environmental sciences.

On Earth, all organisms use carbon as a basic building block of life to construct everything from cells to DNA. Many organisms obtain their energy from carbon-based molecules like sugar, and some form of energy is required to free the carbon atoms from their chemical bonds.

Plants and algae use energy from sunlight to produce their own organic molecules out of carbon dioxide gas taken from the atmosphere or the ocean. The process is known as photosynthesis.

According to Chyba, sunlight would not provide enough energy to sustain life on Europa since its ocean appears to lie "beneath an ice layer too thick to permit photosynthesis."

A likelier source of energy, he concludes, may come from fast-moving, charged particles that pound Europa from the atmosphere of Jupiter. Jupiter has the strongest magnetic field of any planet," Chyba says, more than 10 times stronger than Earth's. When protons, electrons and other particles from space get trapped in Jupiter's magnetosphere, they are accelerated to extremely high velocities.

Europa's orbital path around Jupiter lies deep within this powerful magnetic field, so it receives a continuous barrage of electrified particles or ions. UNQUOTE

http://www.stanford.edu/dept/news/pr/00/000126Europa.html