Cassini Readies for Pass Through Saturn Rings
Wed Jun 30, 2004 05:29 PM ET

By Peter Henderson and Gina Keating

PASADENA, Calif. (Reuters) - NASA's Cassini probe neared Saturn on Wednesday, preparing for its pass through the planet's signature rings in a maneuver that will park it in orbit after a 2.2 billion-mile trip.

Scientists hope the spacecraft will encounter galactic dust at most, since even pea-sized rocks could severely damage the craft as it hurtles along at 50,000 miles per hour.

But they may face a problem on earth -- the antenna in Australia due to track the probe may have to be stowed away due to high winds, in which case scientists would miss the first signals of health from Cassini.

Described as the most capable robotic space explorer built, Cassini will spend four years studying Saturn, its rings and its 31 known moons -- including Titan, the largest.

But first it has to get into orbit in what Charles Elachi, director of Jet Propulsion Laboratory which is overseeing the mission, said were the two most critical hours of the mission as the spacecraft fired its engines to slow down.

"There is no second chance," he said. "There has been a very long time getting close to the 'lord of the rings,' and we will get there tonight," Elachi said.