Controversial Cassini mission could be delayed
For August 8, 1997

By Robyn Suriano

CAPE CANAVERAL, Fla. - A fuel leak in a Titan rocket may delay the start of NASA's Cassini mission to explore Saturn - and give the agency's critics ammunition to attack the safety of the launch.

The leak was discovered Tuesday when technicians were conducting routine tests on the rocket, which is scheduled to carry Cassini into space Oct.6 from Cape Canaveral Air Station.

Air Force officials waited until Thursday to release the information, so they would have access to more test results.

Anti-nuclear advocates are protesting NASA's use of radioactive plutonium to provide electricity for Cassini's science instruments while it tours Saturn..

They worry the mission could endanger public health if the Titan had an accident during launch and plutonium was released into the air.

Officials said the fuel leak in the rocket's Centaur upper stage was not serious and could be fixed.

The only uncertainty is how long it will take to do the work, said Richard Spehalski, NASA's Cassini program manager.

"I'm confident they can fix it without it being a problem," Spehalski said. "We just don't know yet how long it will take. It's too early to tell if it will have an impact on the launch date."

The best time to launch the spacecraft is between Oct. 6 and Nov. 4, so Cassini can take advantage of the most efficient planetary alignment and reach Saturn in 6 1/2 years. If delayed beyond Nov. 4, the spacecraft will take even longer to arrive at its target.

NASA officials said they should know more about the leak today and can make a better assessment of the problem.

Critics of the mission seized on the leak as a sign of danger.
"This is a perfect example that things can and do go wrong," said Bruce Gagnon, coordinator of the Florida Coalition for Peace and Justice, a nonprofit group in Gainesville that is organizing opposition to Cassini.

"No matter how many assurances we get, we know things can go wrong. When you add plutonium into the equation, it's a whole new ballgame." Gagnon said the leak especially is worrisome because the spacecraft is situated in the nose of the rocket, directly above the Centaur upper stage.

However, NASA officials say the plutonium is encased in protective, multi-layered canisters that can withstand most launch accidents.

Even if the canisters were to be breached, only small amounts of the material would be reduced to the tiny particles that can be inhaled or swallowed, leading to cancer, they say.

Named for a 17th-century astronomer, the Cassini spacecraft will travel a roundabout route. The probe will pass Venus twice, Earth once and then Jupiter before heading toward Saturn. It gains speed with each planetary flyby so it can reach its distant target.

If the leak delays the launch beyond Nov.4, NASA has two additional launch opportunities: December 1997 to January 1998, and March to April 1999.

However, the spacecraft will take longer to reach its target if launched during those times because Jupiter will be out of alignment with Saturn, requiring the craft to pass Venus once and Earth twice before heading on.

Once at Saturn, Cassini is to spend four years studying the planet's atmosphere, magnetic field, rings and moons. It also is to drop a probe onto the moon, Titan, to study its nitrogen-rich atmosphere.