On October 15, 1997, NASA launched the Cassini space probe to Saturn from the Cape Canaveral Air Force Station in Florida--with 72.3 pounds of deadly plutonium on-board. This mission has drawn protest from around the world--not just from citizen activists but also from governmental bodies alarmed at the possible catastrophic global consequences of such a mission.

The plutonium is being used to power Cassini's electrical instruments during its voyage to explore the planet Saturn. As Dr. Helen Caldicott, founder of Physicians for Social Responsibility states, plutonium "is so toxic that less than one-millionth of a gram, an invisible particle, is a carcinogenic dose. One pound, if uniformly distributed, could hypothetically induce lung cancer in every person on Earth." Yet NASA has loaded 72.3 pounds of plutonium on Cassini--the most that has ever been used on a non-military space mission.

Since 1961, NASA has launched 24 nuclear-laden missions, three of which have met with accidents. So far, the world has been very, very lucky. Here's a short list of near-misses involving plutonium:

1964: A U.S. navigational satellite fails to achieve orbit and falls from the sky, disintegrating as it burns up in the atmosphere, releasing 2.1 pounds of plutonium.

1970: Astronauts on board Apollo 13 are forced to abandon spacecraft. The ill-fated lunar module plunges into the ocean carrying 8.3 pounds of plutonium.

1986: The Challenger explodes following lift-off. Its next mission was to have been the launch of the Ulysses space probe carrying 24.2 pounds of plutonium.

1989: Galileo probe launched without mishap. Technical difficulties, however, permanently damage spacecraft. 49.25 pounds of plutonium are on board.

1996: Russian Mars space probe crashes back to Earth onto Chile and Bolivia, missing a city by 20 miles--with a half-pound of plutonium on board. The amount of plutonium released is unknown.

January 1997: Delta II rocket explodes on lift off. Residents as far away as 73 miles are asked to stay inside with windows closed and air-conditioning turned off. No plutonium is on board.

In the Cassini mission, there are two periods of extreme danger:

1. The first was when the probe was shot into space on a Titan IV rocket. If the rocket had exploded on the launch pad or in the atmosphere--as the space shuttle Challenger did in 1986--then the lethal plutonium would have spread across wide areas of Florida.

2. NASA wants to give Cassini a boost in speed to get it to Saturn quickly, so instead of relying only on its on-board propulsion system, NASA's plans call for it to be sent to Venus first, and then, after two swings around Venus, Cassini and its 72.3 pounds of plutonium will hurtle right back toward Earth at 42,300 miles per hour. The idea is to use the Earth's gravity to increase Cassini's velocity. Cassini is to pass just 729 miles above Earth on August 18th in what NASA calls a "slingshot maneuver" or "flyby."

A slight miscalculation could result in an inadvertent re-entry, which may cause Cassini to disintegrate in the Earth's 75-mile-high atmosphere. Then, according to City University of New York nuclear physics professor Dr. Michio Kaku, the plutonium--"the most toxic chemical known to science"--would "shower down with a tremendous tragedy for the people of the Earth to result."

What exactly would happen if the plutonium was released during the Earth flyby on August 18th?

NASA reports that if the worst-case scenario occurs--the rocket disintegrates in the atmosphere and the plutonium is released--"approximately five billion of the seven to eight billion people on Earth in 1999 could receive 99% or more of the radiation exposure." NASA then estimates that in 50 years, roughly 2,300 people would develop lung cancer and die from inhaling that plutonium.

However, NASA's estimate of what it labels the "health effects" of an explosion may be grossly and tragically understated. Dr. Ernest Sternglass, professor emeritus of radiological physics at the University of Pittsburgh, has determined that NASA used inappropriate methods to estimate the number of deaths that would be caused. NASA based their estimate on high-level radiation standards derived from the Hiroshima and Nagasaki bombing. But more recent evidence suggests that low-level radiation, the kind to which people would be exposed if Cassini disintegrated, presents a far greater danger. Sternglass warns that the actual death toll from plutonium exposure may be as high as 30 to 40 million people. Even if the odds of an accident are small, is this what NASA is willing to risk to further its space program?

NASA's launching of plutonium into space is completely unnecessary. It insists that its missions are safe and that the plutonium generators on Cassini are indestructible. NASA also maintains that solar power will not work on deep space probes, but its own Jet Propulsion Laboratory (JPL) essentially refutes this claim. In preparation for the Galileo mission (a previous space probe containing radioactive thermonuclear generators used to house the plutonium on-board), NASA also claimed that nuclear power was the only method available. Yet just a few weeks after the launch, JPL was forced, through the Freedom of Information Act, to release a study which stated that the Galileo mission could have been performed with solar power "without changing the mission sequence or impacting science objectives." When the Florida Coalition for Peace & Justice sought an injunction to stop the Galileo launch, NASA lied in Federal Court about the need to use plutonium.

Solar power could have been used on the Cassini mission. In 1994, the European Space Agency (ESA) announced the development of new high-performance solar cells. ESA physicist Carla Signorini stated: "If given the money to do the work, within five years [ESA] could have solar cells ready to power a space mission to Saturn." If the Cassini mission can be performed safely with solar power, why is NASA taking such a large risk by using plutonium? Could it be that NASA and the Pentagon have other motives for using this deadly fuel?

It's another excuse to keep nuclear technology alive and profitable. Lockheed-Martin Corp., which makes the Titan rocket, two years ago took over General Electric Corporation's aerospace division--a maker of plutonium-fueled space systems. In short, building and relying on nuclear technology, and striving to dominate outer space are both in the interests of the same defense-contracting corporations.

You may be surprised that you haven't heard about this story before. In fact, NBC television's parent is General Electric Corporation (which manufactures turbines for nuclear reactors), and CBS's parent is Westinghouse Corporation (which has helped build more than 40% of the world's nuclear power plants). In fact, the Cassini story was named the number one most censored story in 1996 by Project Censored.

Between now and 2009, NASA plans to launch many more plutonium missions, including two nuclear reactors for mining colonies on Mars in 2007. Just as Columbus sailed to discover a new world, NASA and the nuclear industry view outer space as a new market. "Untold riches" await mining colonies on the Moon, Mars, and various asteroids. The Cassini mission will help to develop technology and public support for the nuclearization of space. Meanwhile, Cassini is projected to consume $3.4 billion in tax dollars.

But the Pentagon's long-term goals are clear. The U.S. Space Command is already preparing for a future of U.S. military control in space, which would depend upon the ability to use nuclear reactors as a power source for hypervelocity guns, particle beams, and laser weapons on battle platforms. The U.S. Space Command's document "Vision for 2020," states: "Space forces will emerge to protect military and commercial interests and investment in the space medium ... there will be a critical need to control space to ensure U.S. dominance."

Nuclear power is the key. One Air Force document entitled "New World Vistas: Air and Space Power in the 21st Century" spells it out clearly: "A natural technology to enable high power is nuclear power in space; however, this technology has to date been considered unacceptable due to political and environmental limitations ... Setting the emotional issues of nuclear power aside, this technology offers a viable alternative for large amounts of power in space."

Missions like Cassini become ice-breakers. They keep the nuclear industry viable (Los Alamos, Savannah River, and Oak Ridge all worked on Cassini) and they get the public accustomed to the use of nuclear power in space.

This article was based on the writings of Bruce Gagnon (coordinator of Florida Coalition for Peace and Justice), Michio Kaku (an internationally recognized professor of theoretical physics and a leading critic of the Cassini mission), and Karl Grossman, an award-winning investigative journalist. Paul Cienfuegos is a founding director of Democracy Unlimited of Humboldt County, based in Arcata, CA.