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Special Section: The Cassini Mission

Federal judge turns down bid to stop Cassini

The Cassini probe

NASA not worried about safety of launch

October 11, 1997
Web posted at: 8:13 p.m. EDT (0013 GMT)

CAPE CANAVERAL, Florida (CNN) -- NASA officials sought to reassure the public Saturday that its plutonium-laden Cassini probe to Saturn doesn't pose a threat, while a federal judge in Hawaii turned down a request to block Monday's scheduled launch of the spacecraft.

An environmental attorney in Hawaii, Lanny Sinkin, asked U.S. District Court Judge David Ezra for an injunction stopping the launch, saying NASA is endangering people around the world by putting Cassini, fueled with 72 pounds of plutonium, into space. But Ezra ruled an injunction would not be in the public interest.

Opponents to the launch, including some past and present Kennedy Space Center employees, fear deadly radioactive plutonium could be showered over the Earth if something goes awry, either during liftoff or during a planned flyby of Earth in 1999.

But proponents insist that even if Monday's rocket blast fails, little, if any, plutonium would be released and radiation exposure would be minimal.

"I don't worry about the safety of it," said project manager Richard Spehalski.

Cassini project manager Richard Spehalski

"I'd rather talk about the mission and the science," added a frustrated Spehalski. "The mission is about knowledge, acquiring knowledge, and using a power source like this is a proven technology. It's been demonstrated to be safe."

Start of 11-year-long mission

Cassini -- NASA's largest and costliest interplanetary spacecraft ever -- will take seven years to reach Saturn. Once there, it will spend four years orbiting the planet, its rings and its moons, releasing a probe to land on the largest moon, Titan.

The entire 11-year mission will cost $3.4 billion.

"The mission represents a very rare opportunity to gain significant insights into major scientific questions about the creation of the solar system, prelife conditions here on early Earth and just a host of questions about Saturn itself," said Wesley Huntress Jr., NASA's space science chief.

Huntress promises "fantastic things" when Cassini reaches Saturn
icon 323KB/29 sec. AIFF or WAV sound

NASA officials stress that the plutonium on board is not part of a nuclear reactor generating energy; rather, the energy released by the natural decay of the element will fuel the probe. They say that technology has been used in about two dozen other space missions without incident.

While solar panels are used in many space missions, Spehalski says that is not feasible for Cassini because Saturn is so far from the sun. Its solar panels would have to be the size of two tennis courts in order to generate enough power, he said.

Both NASA and the U.S. Department of Energy, which built the three plutonium "batteries" on Cassini, say that extensive testing of the devices has proven that the chances of a disaster are minimal.

"We've put them through explosions, we've put them through impacts, we've put them next to solid rock fuel and burned them, we've done pressure tests," said Beverly Cook of the Energy Department. "The bottom line is this: We have tested these to the conditions that we will have if there is an accident."

Odds of 1999 reentry 1 in 1 million

NASA has set the odds of a radioactive release during the first 3 1/2 minutes after launch at 1 in 1,400. The chances of a release later in the rocket's climb into orbit narrow to 1 in 476.

In August 1999, Cassini will make a loop around Earth, using its gravitational pull in a sling-shot effect to build speed for the trip to Saturn. The chances that Cassini would malfunction and fall to Earth then are set by NASA at 1 in 1 million.

But Cassini's opponents dispute NASA's figures.

"I find that NASA bureaucrats in some sense are living in fantasyland," says Michio Kaku, a physics professor at City University of New York. "Pure guesswork has replaced rigorous physics. Many of these numbers are simply made up."

Opponents want NASA to redesign Cassini to operate on solar energy -- delaying the probe if necessary until the technology exists to power it without plutonium.

"Saturn isn't going anywhere," said Bruce Gagnon of the Florida Coalition for Peace and Justice. "We are not opposed to space exploration. We just think it must be done properly."

On Saturday, as launch pad workers at the Kennedy Space Center readied a booster rocket for Monday's blastoff, a small group of coalition members held a vigil. While some opponents have hinted they might engage in civil disobedience to try to stop the launch, others plan to leave the area as a precaution.

"It's an obvious course that you don't lie down in front of the steamroller while it's coming down the road," said Jim Ream, a NASA engineer who has taken part in the anti-Cassini protests, to his bosses' chagrin.

Cassini's liftoff is scheduled for 4:55 a.m. Monday EDT (0855 GMT).

Reuters contributed to this report.

Special Section: The Cassini Mission

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