Although the United States has launched some two dozen nuclear-powered spacecraft since 1961, this will be the largest amount of plutonium ever rocketed into space. Cassini critics, fearing a radioactive shower in the event of a rocket explosion during the October 15 launch, vowed to disrupt the event.
Critics fear Earth fly-by Still, activists say the danger is far from over.
Opponents also say they are terrified of the planned Earth fly-by in August 1999, a maneuver designed to give the explorer the gravity assist that will sling it out toward Saturn. While NASA insists that the fallout, if any, from an accident would pose a minimum risk, anti-nuclear activists, pacifists and even a retired space safety officer have banded together to expose what they believe are government lies. They say if the rocket accidentally plunges into the atmosphere during the fly-by, it could shoot lethal plutonium onto Earth. Protesters contend if the probe comes too close , it could re- enter the Earth's atmosphere at 42,000 mph and vaporize, releasing plutonium. The radiation from P-238 is harmless under most circumstances, but breathing in particles can have lethal consequences, opponents say.