STEVE KROFT, co-host:

On October 13th a Titan IV rocket is scheduled to lift off from Cape Canaveral carrying 72 pounds of deadly plutonium; enough plutonium, in theory anyway, to administer a fatal dose to every man, woman and child on the face of the Earth several times over. Got your attention? Well,

It's beginning to get the attention of some people in Florida who want to know what that stuff is doing on top of a rocket and what happens to them if something goes wrong. The mission is called Cassini, and the 72 pounds of plutonium is to power the equipment on board an unmanned space probe during its $3 billion, 11-year journey to study Saturn. The chances of something going drastically wrong are a remote possibility, but that remote possibility has triggered what scientists say is a long-overdue debate on the use of nuclear power in space.

Dr. WESLEY HUNTRESS: We wouldn't be doing this mission if we didn't believe it was perfectly safe and that the risks, even if there should be an accident, are absolutely minimal to the--to the population. Simply wouldn't be doing it.

(Footage of Huntress with Kroft)

KROFT: (Voiceover) Dr. Wesley Huntress is the man in charge of space science and planetary exploration for NASA, including the Cassini Project.

Is it absolutely necessary to have plutonium on this mission?

Dr. HUNTRESS: Yes, it is because otherwise we could not power the spacecraft. We have no means of getting to the outer solar system, just a bit beyond Mars, without using RTGs to power the spacecraft.

(Footage of RTG generators; launching of a rocket; space probe; Cassini spacecraft)

KROFT: (Voiceover) In fact, NASA has been using RTGs, or radioisotope thermoelectric generators, powered by plutonium for more than 30 years, although the agency has not exactly advertised it. They've been used on satellites, on the Apollo moon flights, and in deep space probes. But this mission is different in one key respect: Cassini is carrying far more plutonium, 50 percent more plutonium, than has ever been launched into space before. And that's what's gotten people's attention.

Dr. JOHN GOFMAN: My heart says, `Go Cassini,' because I love the space program. My head says, `Maybe we ought to say, "Whoa."'

(Footage of Gofman; vintage footage of Gofman; footage of Gofman with Kroft)

KROFT: (Voiceover) Dr. John Gofman is Professor Emeritus of biology and molecular biology at the University of California, Berkeley. He was also one of the first scientists to work with plutonium on the Manhattan Project 55 years ago. He thinks it's possible that an explosion on or shortly after launch could rip the RTGs apart and vaporize the plutonium into a cloud of microscopic dust.

What does plutonium do to the human body? What are the risks involved? What's the greatest danger?

Dr. GOFMAN: Plutonium's greatest danger is to be in fine particles. If it's in that form and is inhaled, it can produce pulmonary cancer. And that's not a maybe. We know unequivocally that it produces lung cancer.

(Footage of Gofman and Kroft)

KROFT: (Voiceover) Gofman, who has long been more concerned about the effects of low-level radiation than the mainstream scientific community, acknowledges that the chances of an accident are very remote. But if something unforeseen went horribly wrong, he says the consequences could be drastic.

Dr. GOFMAN: Depending on the winds and where the plutonium comes down and assuming it were in fine particles, you could have numbers like 100,000 or more people who develop lung cancer in a 50-year period as a result of that inhalation. And I have said publicly that if there is such an explosion, you can kiss Florida goodbye.

KROFT: Kiss Florida goodbye?

Dr. GOFMAN: Well, Florida will be there, but it won't be a very good place to live.

(Footage of anti-nuclear activists)

KROFT: (Voiceover) Statements like that from scientists like John Gofman and a small, but vocal band of anti-nuclear activists have people around Cape Canaveral asking some serious questions about the Cassini mission.

Unidentified Man #1: What gives anybody, including the federal government, the right to risk the population's death or--or injury just for space exploration?

(Footage of meeting between populace and NASA officials)

KROFT: (Voiceover) And people are not always satisfied with NASA's answer that there's nothing to worry about.

Unidentified Man #2: If you look at what goes on in every--everyday life, any time one of us gets in a car we put other people at risk. And...

(Footage of meeting)

KROFT: (Voiceover) Opponents of the launch accuse NASA of arrogance. NASA accuses its opponents of ignorance. And there seems to be a little truth in both arguments.

The Cassini probe will begin its journey to Saturn here at Cape Canaveral aboard that Titan IV rocket. What are the chances that something could go wrong? It's difficult to say. Before the space shuttle Challenger exploded, NASA put the chances of a failure at one in 100,000; after the explosion, one in 76. How reliable is the Titan IV? It has an excellent record, but it's not perfect.

(Footage of Titan IV rocket launch; Cassini spacecraft; Dr. Michio Kaku)

KROFT: (Voiceover) Take this 1993 launch of a Titan IV rocket with a $1 billion satellite aboard. A minute and a half into the mission it exploded. NASA says the chances of it happening again on the Cassini mission with plutonium aboard are one in 350. But Dr. Michio Kaku, a prominent physicist at the City University of New York and a leading opponent of the Cassini mission, thinks the chances of something going wrong are a lot greater.

Dr. MICHIO KAKU: I say the true odds are one in 20. A chain is no stronger than the weakest link. The weakest link is the Titan IV booster rocket. Its track record shows failures one in 20 times.

(Footage of Titan IV rocket; Titan IV on launch pad; Kaku)

KROFT: (Voiceover) Since that failure NASA says it's made lots of improvements on the Titan IV, and that even if there was an explosion on the pad or shortly after launch, the chances of any plutonium being released are one in 1,500. Michio Kaku says he wishes he could get those odds in the lottery.

Dr. KAKU: In their heart of hearts they keep believing, `It's not gonna happen. It's not gonna happen.' They keep their fingers crossed, hoping it's not gonna happen. But, look, I don't want to play Russian roulette. I don't want to go like this and say, `It's not gonna happen. It's not gonna happen.'

Dr. HUNTRESS: We are subjected to an incredibly aggressive interagency--very independent process in order to get permission for any of these launches. It involves not just NASA, but it involves the Department of Energy, several other departments. It involves academia. They look at what we do and they review everything we do.

KROFT: This is a full-scale mock-up of the RTG, the plutonium power generator, that will be on board Cassini. The plutonium itself is divided up into more than 200 of these small pieces, encased in heat-resistant metal that's able to withstand high impacts. It's then surrounded by three layers of graphite.

(Footage of men handling RTG generator; RTG testing)

KROFT: (Voiceover) Graphite is a virtually indestructible material NASA uses in its re-entry shields. And it says it's subjected the RTGs to all sorts of blasts and impacts and that they are strong enough to withstand just about any conceivable mishap.

Ms. BEVERLY COOK (Department of Energy): The RTGs that we use on space missions have to be designed to withstand accidents. That is our design requirement.

(Footage of Cook; meeting between NASA officials and the public)

KROFT: (Voiceover) Beverly Cook of the Department of Energy says the plutonium is in ceramic form and designed to shatter like a plate. She tried to reassure this group in Melbourne, Florida, that even if there was an explosion on launch and some plutonium was released, most of it would be in chunks near the launch pad. And NASA says none of it would escape beyond the Kennedy Space Center.

Ms. COOK: There is no condition that's going to cause a release in air. The overpressures in the shrapnel and the explosion in the air will not cause a release. We're not talking about something released in a cloud that's moving anyplace.

Dr. GOFMAN: You know, I've been around the engineering games with weapons testing, and I've just seen so many engineering predictions go astray that I don't get taken in by what NASA says. I hope and pray that NASA is right. But as a scientist, concerned with the public health, I have to take the position that they may be totally wrong.

Unidentified Woman #1: We have ignition and liftoff from Cape Canaveral air station...

(Footage of Delta rocket explosion in midlaunch)

KROFT: (Voiceover) And occasionally things do go wrong, like this launch of a Delta rocket last January.

Woman #1: We have had an anomaly. We're--just had an anomaly of the Delta...

KROFT: (Voiceover) The plume of smoke from the explosion drifted out over the sea and then back over town, south and west of Cape Canaveral.

If there had been plutonium in that plume, it would have been a problem.

Mayor JOHN PORTER: Obviously it would--would have been a problem.

(Footage of Porter; Cape Canaveral city sign)

KROFT: (Voiceover) John Porter is the mayor of the city of Cape Canaveral, whose 8,000 residents live closest to the Cassini launchpad.

Are you convinced this is safe?

Mayor PORTER: Well, I don't think NASA's convinced that it's safe. I think that--you know, it is--that is a matter of o--of opinion, it's a matter of chances...

KROFT: They told us it was...

Mayor PORTER: Yeah, if you look in...

KROFT: They told us it was safe.

Mayor PORTER: ...in their own documents, they--they understand that there are--there is a small chance that--that we could have some problems, if it explodes and--and if the canisters would come apart. It's--and it's slim chance.

(Aerial footage of Cape Canaveral; footage of doctors being trained to treat radiation victims)

KROFT: (Voiceover) Mayor Porter says even the perception of plutonium being released during an accident could destroy the local economy. Who would want to vacation here, ye asks, or buy Florida citrus or seafood? While NASA says the danger to the Florida economy and the public at large is minuscule, the agency is taking no chances. It would seem to be quietly preparing for the worst. At hospitals in central Florida specialists from the US Department of Energy have been training doctors and emergency technicians to treat radiation victims in the event of a Cassini accident.

But if you think it's so safe, why do you need the medical team?

Dr. HUNTRESS: When you're launching a rocket, whether it's carrying plutonium or not, it's--it's a hazardous event. And so it's--it's like--it's like being at a football game with--you know, wi--there's always ambulances at a football game. Nobody expects anybody to get hurt...

KROFT: People think...

Dr. HUNTRESS: ...but you always have contingency plans and make--make sure that you're prepared.

(Footage of radiological control center; response team members at work)

KROFT: (Voiceover) NASA has also set up a radiological control center to communicate with 32 special response teams that will be on alert at the space center and in places like Cocoa Beach, Titusville and the city of Cape Canaveral to monitor radiation levels and to isolate and locate radioactive debris in the event of an accident.

This is from your own environmental impact statement, and I want to read you a couple of things from it. If there's an accident it talks about, quote, "removing and disposing of all vegetation in contaminated areas, demolishing some or all structures and relocating the affected population permanently."

Dr. HUNTRESS: If there should be any such accident.

KROFT: I mean, that sounds fairly drastic.

Dr. HUNTRESS: Well, the--what they're probably talking about mostly is--is the damage on site, near the--near--near the launchpad because there's clearly, when one of these things goes, a lot of damage near the launchpad. And we have to repair all that stuff.

(Footage of Alan Kohn speaking to gathering; Kohn with Kroft; shuttle launch)

KROFT: (Voiceover) There's at least one former NASA employee who might take issue with that. Alan Kohn, who opposes the mission, worked for NASA for 30 years. He's neither a scientist nor an engineer, but he was the emergency preparedness operations officer at the Kennedy Space Center and one of the people responsible for protecting NASA employees and spectators during two previous launches that carried plutonium.

Mr. ALAN KOHN: I had the impression that NASA was fully aware of the fact that plutonium could be released and could fall on civilian populations, regardless of what they say now.

(Footage of Kohn with Kroft)

KROFT: (Voiceover) Kohn thinks NASA has deliberately understated the risk and has kept the public in the dark about the potential dangers of launching plutonium into space.

Why are you so vocal about it now? I mean, you worked for NASA for 30 years.

Mr. KOHN: I feel guilty, quite frankly. I feel like I should--didn't do the job I should have to protect the public. No government agency has the right to put the public at risk without even a public discussion or public hearing about it.

Unidentified Woman #2: My question is to...

(Footage of public meeting with NASA officials; Porter with Kroft)

KROFT: (Voiceover) Now, finally, there is a lot of public discussion going on, and there will be a lot more as the launch approaches. Mayor John Porter thinks it's long overdue.

Are you going to go the launch?

Mayor PORTER: Well, we're at all the launches because we live there.

KROFT: Would you want your family to be in town?

Mayor PORTER: Well, you know, if they were conveniently somewhere else doing something that they normally do, I would say that that would be fine. To answer your question directly, you know, I'd prefer that--that they be somewhere else.

KROFT: Despite his concerns, Mayor Porter and other Florida politicians don't want to stop Cassini. Anti-nuclear activists do and they're threatening to climb fences to disrupt it. One NASA scientist worries about their safety. It's got nothing to do with the plutonium. He thinks some of the demonstrators could get eaten by alligators in the swamps that surround the space center.