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Countdown on track for Cassini launch

Cassini

Protesters hold vigil at White House

October 12, 1997
Web posted at: 11:40 p.m. EDT (0340 GMT)

CAPE CANAVERAL, Florida (CNN) -- The final countdown has begun for the launch of NASA's controversial Cassini mission to Saturn.

The Titan rocket with the Cassini spacecraft on board is scheduled to blast off from Cape Canaveral at 5:55 a.m. EDT Monday (0855 GMT), beginning an 11-year journey to the ringed planet.

However, NASA forecasters said there was a 40 percent chance that wind or rain might force a delay in the planned predawn launch.

Some critics of the Cassini mission -- convinced its plutonium-fueled generators pose a dire threat in the event of a launch disaster -- cleared out of central Florida in advance of liftoff. Cassini contains 72 pounds of highly radioactive plutonium.

But NASA officials involved in the project, who insist the danger is minimal, made a point of bringing their families to view the launch.

Professor Michio Kaku vxtreme Professor Michio Kaku, a nuclear physicist at the City University of New York, discusses the possible dangers of the Cassini launch.

"I have 30 members of my family here right now, including my two granddaughters, and there's more on the way," said project manager Richard Spehalski. "I invited everyone I love to the launch."

Cape Canaveral Mayor John Porter said, "I've met with NASA people, and they've given me their assurances that the launch is safe."

Asked if he would stay in town, Porter said, "Oh, I think I have to. This isn't the time for anyone to think you're abandoning ship."

About 70 protesters held a candlelight vigil outside the White House Sunday night. Several carried signs saying, "Halt nuclearization of space: Stop Cassini."

NASA officials have repeatedly sought to reassure the public that the plutonium-laden Cassini probe to Saturn doesn't pose a threat. Saturday, a federal judge in Hawaii turned down a request to block Monday's scheduled launch.

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.

Canisters which hold plutonium

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.

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 the technology has been used in about two dozen other space missions without incident.

While solar panels are used in many space missions, Spehalski said 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 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."

Protesting against Cassini

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."

Reuters contributed to this report.

 
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