While you stand amazed and in wonder at the fantastic photos being beamed by the Cassini satellite as it orbits Saturn, let's take a little walk down memory lane to 1997.
Most Americans have forgotten that the Cassini launch was big time national news in the fall of 1997, occupying the front pages of our newspapers and national news broadcasts for months. Readers of the Orlando Sentinel declared that it's "disgrace to have that shot, and it's really putting all our lives in jeopardy" and "How dare they gamble with our lives like this." Fouteen year-old Juan Ribero emailed President Clinton asking him to stop the launch: "I told him that we can't learn enough about Saturn to risk lives. It's your choice, Saturn or Earth."
And these residents of central Florida were not alone. Sierra Club spokesperson Geraldine Swormstedt told The Miami Herald, "Floridians are at ground zero if there is an accident at launch. I really feel for people in that area." Congressman Jerrold Nadler (D-NY) told the Boston Globe, "It doesn't take a rocket scientist to see the dangers of the Cassini probe." Daniel Ellsberg of Pentagon Papers fame demanded that the launch be cancelled at a protest rally in front of the White House. The Boston Globe cited the estimates of activist "experts" that the break up of Cassini as it flew back by Earth to get an gravitional boost on its way to Saturn in 1999 could cause from 200,000 up to 40 million deaths.
What were they worried about? The Cassini satellite is powered by three Radioisotope Thermoelectric Generators (RTGs), $ 50 million devices that will rely on the natural radioactive decay of 72 pounds of plutonium-238 to provide heat that can be converted to electricity. The anti-nuke activist community was eager to stop the "nuclearization of space" and the Cassini satellite was exhibit 1 in that campaign. How much danger was there really?
Without rehearsing the exhaustive arguments at the time, keep in mind that plutonium-238 primarily emits alpha particles that travel about three inches and are easily blocked by clothing, the outer level of skin, or a sheet of paper. Futhermore the plutonium is contained in heat resistant ceramic which would break into chunks (not fine dust particles) in an explosion. The ceramic pellets were surrounded by iridium cases that melt at 4,422 degrees Fahrenheit which in turn are surrounded by a heat resistant graphite shield. If the rocket exploded at launch, the ceramic pellets would have posed essentially no danger. In fact, as far back as 1968, NASA controllers were forced to blow rockets carrying satellites with RTGs. Those RTGs were so sturdy that they were recovered and reused in later satellites.
Never mind–as the past seven years have shown we can count on chicken little activists to oppose nearly any new technological project from here to the edges of our solar system and anywhere in between.