Ringing success: How Cassini spacecraft has altered knowledge of enigmatic Saturn
It was a tense moment. The little Cassini spacecraft was hurtling through the black void of space at 54,500 miles per hour. After a seven-year journey, the probe was finally approaching its destination – Saturn – in June 2004. But the spacecraft needed to slow down for the planet’s gravity to pull it into its orbit. So project engineers were going to pump the brakes by carrying out a controlled burn. It was a planned procedure, but a risky one.
Igniting the thrusters too long could burn up much of the spacecraft’s precious fuel, cutting the multibillion-dollar mission tragically short. Not slowing it enough would leave it flinging past Saturn, lost forever in space. The plan was to fire the engine for 96 minutes. If it failed to burn for even four of those minutes, the probe would pass ignobly into oblivion.
Dozens of mission scientists and their families converged in an auditorium at Pasadena City College in California to witness the moment. Adults passed the time and soothed nerves by answering a steady stream of questions about the mission from children. As the moment neared to find out if the burn was successful, a hush fell over the crowd. Cassini project scientist Linda Spilker couldn’t relax in her seat. She stood frozen.
Then, at 9:12 in the evening local time, the radio transmission arrived from 934,431,318 miles away, blinking the result on a large auditorium screen.
“We waited and waited, and finally there’s the signal ... boom!” Dr. Spilker says, recalling that warm California night of June 30. “Right on the line [in Saturn’s orbit]. We were cheering, hugging each other.”
Thus began Cassini’s auspicious quest to increase our knowledge of Saturn
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