The Cassini spacecraft just crashed into Saturn

By Sarah Kaplan September 15, 2017

PASADENA, Calif. — NASA scientists just received their last message from the Cassini spacecraft, which plunged into Saturn early Friday morning. Those final bits of data signal the end of one of the most successful planetary science missions in history. “The signal from the spacecraft is gone and within the next 45 seconds so will be the spacecraft,” program manager Earl Maize reported from mission control at NASA's Jet Propulsion Laboratory, just after 4:55 a.m. local time. “This has been an incredible mission, an incredible spacecraft, and you're all an incredible team.” Cassini was the first human probe to orbit Saturn; launched in 1997 and inserted into orbit in 2004, it revolutionized our understanding of the ringed planet. The spacecraft revealed the structure of Saturn's rings and, by delivering the Huygens probe to the moon Titan, executed the first landing of a spacecraft in the outer solar system. It also exposed two moons — Titan, a land of methane lakes, and Enceladus, which has jets of water streaming from its southern pole — as prime targets in the search for life beyond Earth.

After 13 years in orbit, Cassini leaves researchers with still more mysteries to ponder: They don't know the length of the Saturn day or understand the quirks of its magnetic field. And it will fall to a future mission to discover whether one of Saturn's potentially habitable moons could truly be home to alien life. “Most of what we have in science textbooks about Saturn comes from Cassini,” JPL Director Mike Watkins said. “The discoveries are so compelling, we have to go back.” Just after 3:30 a.m. California time on Friday, Cassini entered Saturn's atmosphere, plummeting at a pace of about 77,000 miles per hour. For a few minutes, the spacecraft's thrusters fought to keep its high-gain antenna pointed toward Earth, so it could continue to send back real-time data from this uncharted territory. During those last moments, the spacecraft's instruments sampled the molecules in the planet's atmosphere — information that scientists will use to understand the planet's formation and composition. Minutes later Cassini vaporized, just a small flash of light streaking across an alien sky. But because Saturn is so distant, Cassini's final signals didn't reach Earth until 83 minutes after the spacecraft was gone. That last communication was displayed as a green spike of data on a screen above mission control. The spike shrank, then flickered, then flatlined.

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