Anti-nuke Scaremongers Threaten Saturn Mission Our View: Next month's planned space probe may not lift off if plutonium paranoia rules. Next month, NASA hopes to launch one of its most ambitious projects yet - the Cassini space probe to Saturn. The mission has a mere five-week window for launch because Cassini can't get to Saturn by rocket alone. First, the probe must shoot around Venus. Using gravitational pull, it then would slingshot back toward Earth. Earth's gravity would accelerate Cassini across the billions of miles of space to reach Saturn by 2004.
If a few anti-nuclear activists have their way, Cassini will never lift off. Their fear: 72 pounds of radioactive plutonium in the probe's instrument power pack could endanger life on Earth if anything goes wrong.
The 1986 Challenger disaster proved that NASA can slip on safety. But the agitation about Cassini's plutonium has more to do with paranoia than performance. The facts contradict the fears.
Claim: If the power packs, called radioisotope thermoelectric generators (RTGs) break open, 200,000 may die.
Fact: The worst case would be if Cassini burned up in the atmosphere instead of swinging around Earth. NASA, supported by an independent review headed by MIT, says the odds of that are one in a million. If it did, the release of plutonium could expose people to an extra rem of radioactivity, a 40th of a dental X-ray. That might lead to, at most, 120 cancer deaths over 50 years and serious contamination on 5.8 square miles of land.
Claim: RTGs are unsafe and untested.Fact: Plutonium in an RTG is nonweapons grade, so it won't explode. Made into ceramic pellets
the size and shape of marshmallows, the plutonium won't easily pulverize into breathable form that could cause cancer. Each 4-ounce pellet is wrapped in iridium. Three layers of re-entry- grade graphite surround them. Two national labs have subjected RTGs to extreme heat pressure and pounding to ensure safety. And they've survived 23 space missions and three accidents without any significant release of plutonium.
Claim: There's no need to use RTGS; Europe has high-energy solar cells to replace them.
Fact: The European Space Agency says its cells can't do the job. Two solar panels, each bigger than two tennis courts, would be needed to replace the RTGS. That's too big for a rocket to lift into space.
Nothing is riskless. But Cassini's risks are so low as to be meaningless. And the knowledge Cassini can provide is immense. Saturn and its unique rings hold vital secrets about our solar system. The chemical fog of its moon Titan may even provide answers about the origins of this great blue planet Earth and life upon it.
To be deterred from that journey by the false fears raised by Cassini's critics would truly be a giant leap backward for mankind.
Mission Not Worth risks Opposing view: Remember the Challenger or tragedy? Let's not invite another space disaster. By Karl Grossman NASA is taking unnecessary risks, endangering people and the planet by its use of plutonium on space devices. And it's not being honest about solar alternatives.
In 1985, I learned about two plutonium fueled space probes to be lofted by shuttles in 1986. One was to be the ill-fated Challenger's next mission. My inquiries under the Freedom of Information Act about the consequences of an accident were blocked. And NASA insisted: Nothing to be concerned about anyway; the likelihood of a "catastrophic" accident is 1 in 100,000.
Then came the Challenger explosion. NASA promptly changed its odds to 1 in 76. In science, one knows true probability only by empirical evidence, by reality.
NASA rescheduled those shots, insisting there was no alternative to plutonium. For years it stonewalled my requests for information regarding alternatives. Only after the Galileo probe was launched did I receive NASA analyses like one concluding Galileo "could be performed with a solar array power source."
NASA says its nuclear program has been a "success." In reality, three of 26 nuclear shots have met with mishaps, including the SNAP-9A, which disintegrated in 1964, spreading plutonium all over the Earth.
Now it's Cassini, with more plutonium than ever. The launch on a Titan IV rocket (with a 5% failure rate) is only one disaster waiting to happen. Then there's the 1999 "flyby" when the probe and its 72 pounds of plutonium dioxide come hurtling back at 42,000 mph less than 500 miles overhead. If there is "inadvertent re-entry," NASA says, plutonium will be released as "vapor or respirable particles" and "approximately 5 billion [people] could receive 99% or more of the radiation exposure." NASA is then prepared to "ban future agricultural land uses" and "relocate affected population permanently."
This colossal risk, most importantly, is not necessary: New, high-efficiency solar cells could be used to substitute for plutonium on a redesigned Cassini probe.
We're on a countdown to nuclear space disaster, on Cassini or other planned shots. The use of nuclear power on space devices is not worth the risk. Let's explore space but do it safely, not exposing large numbers of people to cancer-causing radiation and rendering part of the Earth uninhabitable.
Karl Grossman, professor of journalism at State University of New York College at Old Westbury, is author of The Wrong Stuff- The Space Program's Nuclear Threat to Our Planet.
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