PASADENA, Calif., July 13 (UPI) -- When the Cassini spacecraft dashed through a gap in Saturn's rings on June 30, it was pelted with ring dust, mission controllers reported.
Although Saturn's ring gap appeared empty, it actually contained innumerable bits of ring dust, which plowed into the spacecraft at a relative speed of approximately 45,000 miles an hour, or 20 kilometers per second.
"When we crossed the ring plane, we had roughly 100,000 total dust hits in less than five minutes," said Cassini science team member Don Gurnett of the University of Iowa.
The particles were small, however, "comparable in size to particles in cigarette smoke," he said, and most of the hits were endured by the spacecraft's tough, high-gain antenna.
Each time a dust particle hit Cassini, the impact produced a puff of plasma, a tiny cloud of ionized gas. Cassini's radio and plasma wave science instrument was able to count these clouds, and found there were as many as 680 puffs per second.
The spacecraft reported no unusual activity due to the hits and performed flawlessly, NASA scientists said, going into orbit around Saturn successfully to begin Cassini's four-year mission of exploration of Saturn and its moons.
