NASA's nuclear gamble - October 1997 launch of a Cassini space probe which will carry 732.3 lbs of potentially dangerous plutonium: includes information on anti-launch activities - Cover Story

Progressive, The, Sept, 1997 by Karl Grossman

In October, NASA is planning to launch the Cassini space probe to Saturn. The probe will carry 72.3 pounds of plutonium, the most ever put on a space device.

Plutonium is the most toxic substance known. "It is so toxic," says Helen Caldicott, president emeritus of Physicians for Social Responsibility, "that less than one-millionth of a gram is a carcinogenic dose. One pound, if uniformly distributed, could hypothetically induce lung cancer in every person on Earth."

NASA intends to launch Cassini on October 6 on top of a Lockheed Martin Titan IV rocket. Titan rockets have had a series of mishaps, including a 1993 explosion in California that occurred less than two minutes after the launch. The blowup destroyed a $1 billion spy-satellite system. Fragments from the satellite fell into the Pacific Ocean.

If the Cassini probe blows up, we will be in a heap of trouble, as plutonium could rain from the skies.

The true death toll "may be as much as thirty to forty million people," says Ernest Sternglass, professor emeritus of radiological physics at the University of Pittsburgh School of Medicine.

"Remember the old Hollywood movies when a mad scientist would risk the world to carry out his particular project?" asks Horst Poehler, a scientist who worked for NASA contractors at the Kennedy Space Center for twenty-two years. "Well, those mad scientists have moved to NASA."

The plutonium used on space probes is not the Plutonium-239 isotope used in atomic bombs and built up as a byproduct in nuclear power plants. It is another isotope, Plutonium-238, which is 280 times more radioactive than Plutonium-239. It is more radioactive because it has a far shorter half-life, 87.8 years compared to 24,500 years for Plutonium-239. The plutonium on Cassini is to be used for fuel in the three generators to produce an average of just 745 watts of electricity to power the probe's instruments. Its shorter half-life means it produces a great deal of heat as it decays. Radioisotope thermoelectric generators (RTGs) translate that heat to electricity.

"They call the RTGs indestructible," says Alan Kohn, a thirty-year NASA veteran-turned-whistleblower. "They're indestructible just like the Titanic was unsinkable."

Nasa insists the Cassini mission is safe. The odds against Cassini exploding on launch and releasing plutonium into the air are 1,500 to one, the agency says.

Those are pretty poor odds," Kohn says. "You bet the lottery, and the odds against you there are fourteen million to one."

In its final environmental-impact statement dated June 1995 for the Cassini mission, NASA warns that, "Approximately five billion of the estimated seven to eight billion world population could receive 99 percent or more of the radiation exposure" if an "inadvertent reentry occurred."

NASA defines a launch accident as one of the potential problems with the Cassini probe. The environmental-impact statement outlines several scenarios in which plutonium might be released, including an explosion of the Titan IV, which is to loft the Cassini into orbit, or an explosion of a small rocket, a Centaur, which is to propel it on to Saturn.

In January, a Delta Il rocket created a fiery explosion during its launch at the Cape Canaveral Air Station. A toxic cloud of chemicals floated down the Florida coast. Residents as far off as Vero Beach, seventy-three miles away, were told to remain indoors to avoid contamination. "This is a sample of what could happen on Cassini -- except this time the cloud could contain plutonium," says Bruce Gagnon of the Florida Coalition for Peace & Justice.

NASA's environmental-impact statement does not predict much danger of an accident for Cassini after the launch as the probe travels over the Atlantic. If there is an accident then, the radioisotope thermoelectric generators containing the plutonium would probably fall into "the ocean waters ... sinking with no release expected."

But trouble could reappear when Cassini flies over Africa.

If the Titan IV or Centaur, or both, explode over Africa and the radioisotope thermoelectric generators "impact rock surfaces," as NASA euphemistically puts it, the probe would probably release plutonium on the continent.

NASA says the third Cassini problem area -- and the most dangerous point in the mission -- will be the Earth "flyby" scheduled for 1999. This is where five billion people could be exposed.

NASA intends to send the probe to Venus, where it will circle the planet twice, and then hurtle back toward Earth for a fast and low flyby designed to use gravity to increase Cassini's velocity so it can reach Saturn. NASA calls this a "slingshot maneuver."

The probe is supposed to buzz 312 miles above the Earth at 42,300 miles per hour in August 1999. But if there is a miscalculation and Cassini comes in too low, it could burn up in the seventy-five-mile-high atmosphere and rain plutonium back down on Earth.

As it flies by Earth ... if there is a small misfire [of Cassini's] rocket system, it will penetrate into the Earth's atmosphere," explains Michio Kaku, professor of nuclear physics at the City University of New York. "It will, like a meteor, flame into the Earth's atmosphere.... It will vaporize, release the payload, and then particles of plutonium dioxide will begin to rain down." Plutonium dust "will rain down on people's hair, people's clothing, get into people's bodies. And because it is not water soluble, there is a very good chance that it could be inhaled and stay within the body, causing cancer over a number of decades."