Cassini's grand finale occurred on September 15, 2017, when it took a death plunge into Saturn to facilitate its own destruction. These are some of the last—and some of the most meaningful—photos the spacecraft sent before is demise.
The rings of Saturn, taken on September 13, 2017 [Image by NASA/JPL-Caltech/Space Science Institute]
The Cassini mission was a joint effort by NASA, the European Space Agency, and the Italian Space Agency. Spacecraft Cassini was launched on October 15, 1997, and reached Saturn—its destination—on July 1, 2004. Cassini spent 13 years in Saturn's orbit, and its entire mission lasted a total of 19 years and 335 days.
An image of Enceladus, taken on September 13, 2017 [Image by NASA/JPL-Caltech/Space Science Institute]
During its orbit around Saturn, Cassini was able to take numerous photos and make numerous discoveries about Saturn and its moons. Cassini also brought with it the lander called Huygens, a pioneering spacecraft. It was the first spacecraft to land on a moon not our own, it was the first spacecraft to land on Saturn's moon Titan, and it made the furthest landing from Earth that a spacecraft has ever made. This mission led to the discovery that Titan has lakes made mostly of methane on its surface, and that Titan possibly has an underground saltwater ocean.
Saturn, taken on September 13, 2017 [Image by NASA/JPL-Caltech/Space Science Institute]
The mission has made several important discoveries, but it's all good things must come to an end. Astronomers estimated that eventually, Cassini's fuel stores will be depleted. They decided that destroying the spacecraft by having it crash into Saturn was the best end to Cassini. Scientists can't risk biological contamination of Saturn's moons—especially Titan and Enceladus—which are prime locations for the search for extraterrestrial life. If microbes that may be on Cassini contaminate these moons, it may cast doubt on findings of extraterrestrial life, should they ever happen.
Thus, on September 15, 2017, Cassini's grand finale took place as the spacecraft made its swan dive into Saturn. The spacecraft had been taking photos and gathering data in the days leading up to its fiery death. It took its last photo at 12:58 p.m. PDT on Thursday, September 14. Mission control began receiving the data about two hours after this, and Cassini also transmitted real-time data of its dive down to Saturn. The last photo that Cassini ever took was of the spot in Saturn's atmosphere where the spacecraft met its end.
See the rest of the photos taken by Cassini here.
The last image that Cassini ever took, showing the patch of Saturn's atmosphere were it will meet its end [Image by NASA/JPL-Caltech/Space Science Institute]
Scientists expected Cassini's time of death to be 4:55 am PDT. Cassini sent its final transmission to Earth at 4:55:46 am PDT. NASA then lost contact with the probe, which has presumably perished in Saturn's atmosphere. According to NASA official, it's likely that Cassini disintegrated about 45 seconds after it sent that final transmission.
Cassini program manager Earl Maize announced the end of the mission after losing connection with the spacecraft. The mission team stood and applauded at Maize's announcement, triumphant but somber.
Both scientists and the general public had expressed affection for Cassini in the months leading up to its demise. After all, the spacecraft spent 13 years sending us amazing images of Saturn and its moons. “It's just very heartening,” says Maize of the outpouring of affection and support. “Because it's part of what we try to do—to extend everybody out to Saturn.”
Cassini's grand finale was grand indeed.
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