Seven years ago, when Alan Kohn needed a budget to do his job at Kennedy Space Center, he threatened his bosses. "I sort of forced the budget from the payload manager by threatening to go to the protest groups," Kohn remembers. He got $10,000 to protect 20,000 government workers from the possible radiation fallout in the event of an accident. As emergency-preparedness officer for the Galileo and Ulysses missions, Kohn turned the buildings at KSC into fallout shelters, but he didn't tell the people in Brevard County to do the same to their homes. He received a commendation for his work and kept quiet about the potential danger. Last month Kohn broke his silence, warning Central Floridians to get out of the area during the Oct. 6 launch of the Cassini deep space probe, which will carry more than 72 pounds of plutonium-238 to generate electricity. "I call on the people of this community to protect themselves, their families and their children, to protect their neighbors," Kohn told a group of protesters outside the gate on June 14. He makes a distinction between himself and the Florida Coalition for Peace and Justice, the group that made it possible for him to do his job in 1990. Unlike Bruce Gagnon, who coordinates the coalition, Kohn is in favor of nuclear materials in space -- and even nuclear reactors -- provided the rocketry is made safer. "I'm in favor of it," says Kohn. "But my conscience started to bother me. How can we put the public at risk without even informing the public? You need informed consent in a democracy. That's the definition of democracy." He says NASA's stated 1,500-to-one odds of a mishap are "unacceptable." NASA's risk assessments have also been called into question by a noted physicist who is scheduled to address a demonstration at 2 p.m. Saturday at Cape Canaveral Air Force Station. Dr. Michio Kaku, a City University of New York professor who opposes the nuclearization of space, says NASA's accident probability figures vastly understate the danger of a Cassini crash. "They use the same discredited methodology (e.g. event tree analysis) which is used for nuclear power plants, which failed completely to predict Three Mile Island and Chernobyl," Kaku says. "They don't factor in human failure, multiple failures, common-mode failures and design flaws, which actually have caused most of the great disasters of the 20th century." Given that the Titan IV rocket, on which Cassini will ride, fails about one out of 20 times, Kaku estimates the real failure rate is one in 20. Kaku also questions NASA's estimate of a possible death toll in the event of an accident. The space agency puts the number at 2,300 over 50 years. "They have taken the lowest possible estimates at every step in their calculation," Kaku says. "NASA is not considering the maximum possible accident at all." By taking the high estimates, Kaku says a Cassini catastrophe could kill 200,000 people or more. Gagnon's coalition has people going door-to-door in Brevard County, hanging messages on door knobs warning of the risks. The coalition has a petition with thousands of signatures it has directed to President Clinton to stop the launch and also plans civil disobedience. "Now's the time for international outrage and protest," says Gagnon. "Congress must yet appropriate our tax dollars to pay for these future nuclear space projects." Kohn, who retired from NASA in 1994, thinks the launch will go off as scheduled. "With $1.5 billion spent, with the momentum behind it, I believe we don't have the clout to stop it," he says. "And I believe what they tried to do is depict those people trying to stop it as a bunch of nuts. Meanwhile, some NASA people will quietly get their families out of town."