NASA's nuclear gamble.

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."

As for the death toll, NASA says that only "2,300 health effects could occur over a fifty-year period to this exposed population." These "latent cancer fatalities," says NASA, would be "likely to be statistically indistinguishable from normally occurring cancer fatalities among the world population."

But Sternglass at the University of Pittsburgh School of Medicine says NASA's environmental-impact statement "underestimates the cancer alone by about 2,000 to 4,000 times. Which means that not counting all the other causes of death -- infant mortality, heart disease, immune-deficiency diseases, and all that -- we're talking in the order of ten to twenty million extra deaths."

Helen Caldicott says NASA fails to understand the especially dangerous characteristics of plutonium and the health impacts from "chronic, long-term exposure. This is incredibly deadly stuff." Also, she says, NASA has drastically underestimated the impact by basing it on an "average dose for the overall world population," and not providing for those people who would receive larger doses of plutonium.

The shielding around the plutonium is "fingernail thin. It's a joke," says former NASA scientist Poehler. It consists of an iridium shell 3/128 inches thick, two 1/4-inch graphite shells, "insulating foil and, finally, a 1/16 inch-thin aluminum housing. Hardly what one would call 'heavily shielded.'" Poehler cites thirty NASA tests that acknowledge that plutonium in various impact situations could be released.

Indeed, the NASA environmental-impact statement admits that if Cassini breaks up in the 1999 flyby, much of the plutonium fuel would disperse as "vapor or respirable particles" -- just the form in which lethal doses of plutonium could be breathed in by many people.

An accident involving the 1999 Earth flyby could be "the mother of all accidents," says Poehler.

The amount of plutonium NASA admits could be dispersed in a flyby accident "represents an astronomical quantity of a potent alpha-emitting cancer producer," says John Gofman, professor emeritus of medical physics at the University of California at Berkeley and former associate director of the Lawrence Livermore National Laboratory. "The number of cancer doses is so high as to make calculations extraneous," says Gofman. "Scientists and engineers in control of their faculties would surely have eliminated this project from their agenda. Yet it appears that is not the case."

NASA says in its environmental-impact statement that 32 to 34 percent of the plutonium on Cassini would be released in a flyby accident. But, considering the speed at which Cassini would hit the Earth's atmosphere, the probe "would completely disintegrate" and "all the plutonium" would fall out, Kohn says. He calls the flyby scheme "unconscionable."

In a chart in its environmental-impact statement, NASA outlines the "decontamination methods" it will apply if plutonium is released in a Cassini accident. NASA's plan if the plutonium rains down on "natural vegetation" is: "Remove and dispose all vegetation. . . . Remove and dispose topsoil. . . . Relocate animals." If the plutonium comes down on a region of "agriculture," NASA's plan bans "future agricultural land uses."

As for the plutonium falling on an "urban" area, NASA's plan says: "Impose land-use restrictions . . . Demolish some or all structures. . . . Relocate affected population permanently."

Before Cassini, NASA had already launched missions involving nuclear generators. The two biggest were the Galileo and the Ulysses. In 1989, the Galileo (with forty-nine-and-a-quarter pounds of plutonium fuel on board) went on a mission to Jupiter. In 1990, the Ulysses (with twenty-five pounds of plutonium) went on an orbit of the sun. The Ulysses had been scheduled to launch years earlier; it had been slated to be the next mission to follow the ill-fated Challenger disaster of 1986.

Alan Kohn served as NASA's emergency-preparedness operations officer for the Galileo and Ulysses launches. He was not impressed with the instructions his superiors gave him.

"They didn't even let me do that job," he told protesters at a Florida Coalition for Peace & Justice demonstration at Cape Canaveral in June. "I was told that the job was cosmetic, that nothing was going to happen and I should just sit and counsel everyone in the radiation-control center and do nothing, and in case of disaster, I could take all protective measures at that time. The only protective measure I could have taken at that time, of course, would have been to wet my pants. And my own immediate management told me: Lay off, keep a low profile, don't let the public know, above all don't let the protest groups know that there is any danger. I disobeyed orders. I provided that all the buildings should be turned into fall-out shelters, that air conditioning be shut off, that buildings be sealed, the doors be sealed, that people who were going to work outside would be put in bunny suits and given gas masks."

What NASA was going to do in case of a launch accident, said Kohn, was "monitor the fall-out as the plutonium fell." There was "exactly nothing," in fact, that could have been done to stop the plutonium from raining down. Furthermore, Kohn said, he saw NASA's projection of "potential fall-outs, which depended on wind, speed, and the direction and height at which the explosion took place." They extended as far as highly populated Orlando, west of Cape Canaveral.

"It is time to put a stop to NASA's freedom to threaten the lives of the people here on the Earth," said Kohn. As rain fell and lightning flashed, Air Force and NASA security personnel watched Kohn speak. "I don't know what they think gives them the right to do a thing like this."

Nevertheless, the U.S. government is pushing ahead on the launch of the plutonium-fueled Cassini probe and on many more space shots involving nuclear power.

Perhaps most outrageous, there is no need to use deadly plutonium at all. In 1994, the European Space Agency (ESA) announced a breakthrough in the development of "new high-performance silicon solar cells for use in future, demanding deep-space missions." It stated: "Until now, deep-space probes had to use thermonuclear power generators like the so-called RTGs. . . . As RTG technology is not available in Europe, ESA therefore attempted to develop a power source based on very high-efficiency solar cells." In what it termed a "technology milestone," the European Space Agency developed cells with a 25 percent efficiency, "the highest efficiency ever reached worldwide. . . . ESA expects that the high-performance silicon solar cells could profitably be used in deep-space missions."

In 1995, European Space Agency physicist Carla Signorini told the newspaper Florida Today: "It given the money to do the work, within five years the European Space Agency could have solar cells ready to power a space mission to Saturn."

In March of this year, Gerhard Strobl of Deutsch Aerospace -- the company that led the European Space Agency contractors in the solar-cell project -- said his firm could provide a solar system for a redesigned Cassini probe. He noted that his firm was building a solar-powered drive to power the European Space Agency's Rosetta space probe, which the agency plans to launch to "go beyond the orbit of Jupiter" and rendezvous with a comet. The solar cells on Rosetta will be producing 500 watts of electricity. Said Strobl: "We solved the basic problem of high-efficiency solar cells for space."

Still, NASA insists on sticking with plutonium power -- and the chance of colossal harm -- on the Cassini mission. Why?

There are corporate and governmental pressures. The General Electric Company, for decades the manufacturer of the plutonium-fueled radioisotope thermoelectric generators, pushed for their use. In recent times, GE's aerospace division became part of Lockheed Martin, which has continued lobbying where GE left off. In 1995 a subcommittee of the House Appropriations Committee zeroed out the Cassini mission based on its high cost, which NASA now estimates at $3.4 billion, the most expensive single space project to date. However, in following days, "lobbyists from Lockheed and NASA were all over us," said an aide to the House Appropriations Committee. The subcommittee's Cassini cut was restored.

The U.S. Department of Energy's national nuclear laboratories -- such as Oak Ridge, Los Alamos, and Brookhaven -- have also been pressuring for more use of nuclear power in space. And the Department of Energy itself wants to pursue its mission of promoting atomic technology.

There is also a military connection. U.S. military strategy now refers to space as the "ultimate high ground."

"Yesterday's high ground of remote ridge fines and distant hilltops has a modern corollary: space. Our technologies are the ladders that enable military commanders, now and in the future, to reach that ultimate high ground," said Colonel Mike Heil of the Air Force's Phillips Laboratory. A current Phillips brochure describes the mission of one of its facilities as "supporting the war fighter" and "helping control space for the U.S."

General Joseph W. Ashy, commander-in-chief of the US. Space Command until he retired last September, told Aviation Week & Space Technology in 1996 that the U.S. Air Force intends to "expand into" space. "We will engage terrestrial targets someday -- ships, airplanes, land targets -- from space," the general said. "We will engage targets in space, from space. . . . It's politically sensitive, but it's going to happen. Some people don't want to hear this, and it sure isn't in vogue . . . but -- absolutely -- we're going to fight in space. We're going to fight from space, and we're going to fight into space."

An Air Force report issued last year states, "In the next two decades, new technologies will allow the fielding of space-based weapons of devastating effectiveness."

There is a problem for the kind of space-based weaponry -- lasers and particle beams and the like -- that the U.S. military envisions: "power limitations," notes the report. It declares: "A natural technology to enable high power is nuclear power in space. . . . Setting the emotional issues of nuclear power aside, this technology offers a viable alternative for large amounts of power in space," the report states.

That's where NASA's nuclear-fueled missions come in. Since the U.S. military seeks nuclear-powered weaponry in space, NASA, which has been working increasingly in coordination with the Pentagon, has an additional incentive to favor nuclear over solar power in space.

"Nuclear energy in outer space," says Michio Kaku, "is the linchpin" of the U.S. space program. "What we are headed for is a nuclear-propelled rocket with nuclear-propelled lasers in outer space. That's what the military and that's what NASA would really like to do. Ultimately, what they would like to do is have nuclear-powered battle stations in outer space. That's what all of this is leading up to."

The United States wants to "attain mastery of outer space with the atom," Kaku says. "We have to stop these Cassinis before we have genuine nuclear booster rockets and nuclear power plants in outer space. We have to send a signal to NASA and the Pentagon that we're not going to tolerate the nuclearization of outer space."

Even some people inside NASA are worried about Cassini. Chief scientist Frances Cordova acknowledged to the trade-industry publication Space News that the Titan IV "does not have a 100 percent success rate" and use of it on the Cassini mission "is truly putting all your eggs in one basket -- your eighteen instruments on one firecracker." She said: "We can't fail with that mission. It would be very, very damaging for the agency."