Cassini's first dive, finds "The Big Empty"
The Cassini spacecraft successfully completed its first dive between the planet Saturn and its rings, something no other craft had done before. Before attempting the dive, scientists weren't sure exactly how much dust/debris would exist in this gap. As a precaution, the orbital scientists oriented Cassini so that its radio antennae pointed in the direction of its trajectory to help protect some of its more sensitive instruments. While performing the dive, mission scientists performed measurements to see just how dusty the environment between the rings was, and it turns out... it's very empty! Mission scientists converted the data into audio tracks to listen for 'pings:' sounds made by small particles hitting the space craft. They heard very few.