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Jan. 18, 2019: New research from Cassini's mission finale in 2017 sheds light on some longstanding mysteries.
- The final close passes by the rings and planet enabled scientists to measure the length of a day on Saturn: 10 hours, 33 minutes and 38 seconds.
- Researchers also found Saturn's rings are relatively new. They may have formed during the age of dinosaurs on Earth.
For more than a decade, NASA’s Cassini spacecraft shared the wonders of Saturn and its family of icy moons—taking us to astounding worlds where methane rivers run to a methane sea and where jets of ice and gas are blasting material into space from a liquid water ocean that might harbor the ingredients for life. Cassini revealed in great detail the true wonders of Saturn, a giant world ruled by raging storms and delicate harmonies of gravity.
Cassini carried a passenger to the Saturn system, the European Huygens probe—the first human-made object to land on a world in the distant outer solar system.
After 20 years in space—13 of those years exploring Saturn—Cassini exhausted its fuel supply. And so, to protect moons of Saturn that could have conditions suitable for life, Cassini was sent on a daring final mission that would seal its fate. After a series of nearly two dozen nail-biting dives between the planet and its icy rings, Cassini plunged into Saturn’s atmosphere on Sept. 15, 2017, returning science data to the very end.
Cassini-Huygens was a mission of firsts. First to orbit Saturn. First landing in the outer solar system. First to sample an extraterrestrial ocean. Cassini expanded our understanding of the kinds of worlds where life might exist. Cassini-Huygens revealed Titan to be one of the most Earth-like worlds we’ve encountered and shed light on the history of our home planet. Cassini was, in a sense, a time machine. It revealed the processes that likely shaped the development of our solar system. Cassini’s long mission enabled us to observe weather and seasonal changes on another planet. Cassini revealed Saturn’s moons to be unique worlds with their own stories to tell. Cassini showed us the complexity of Saturn’s rings and the dramatic processes operating within them. What Cassini found at Saturn prompted scientists to rethink their understanding of the solar system. Cassini represented a staggering achievement of human and technical complexity, finding innovative ways to use the spacecraft. Cassini revealed the beauty of Saturn, its rings and moons, inspiring our sense of wonder.
10 Ways Cassini Mattered
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Notable Explorers
Sarah Milkovich
Planetary Geologist and Science Systems Engineer
"Be curious about everything -- take every opportunity that presents itself to learn new things."
Quick Facts
2.5 million commands executed
4.9 billion miles traveled since launch (7.9 billion kilometers)
635 GB science data collected
~4,000 science papers published
6 named moons discovered
294 orbits completed
162 targeted flybys of Saturn's moons
453,048 images taken
27 nations participated
360 engine burns completed
What’s Next?
Before the mission ended, Cassini’s was an already powerful influence on future exploration. In revealing that Enceladus has essentially all the ingredients needed for life, the mission energized a pivot to the exploration of "ocean worlds" that has been sweeping planetary science over the past couple of decades.
Lessons learned during Cassini's mission are being applied in planning NASA's Europa Clipper mission, planned for launch in the 2020s. Europa Clipper will make dozens of flybys of Jupiter's ocean moon to investigate its possible habitability, using an orbital tour design derived from the way Cassini explored Saturn.
Farther out in the solar system, scientists have long had their eyes set on exploring Uranus and Neptune. So far, each of these worlds has been visited by only one brief spacecraft flyby (Voyager 2, in 1986 and 1989, respectively). Collectively, Uranus and Neptune are referred to as ice giant planets. A variety of potential mission concepts are discussed in a recently completed study, delivered to NASA in preparation for the next Decadal Survey—including orbiters, flybys and probes that would dive into Uranus' atmosphere to study its composition. Future missions to the ice giants might explore those worlds using an approach similar to Cassini's mission.
More Resources
Planetary Data System (search for Cassini for all available data)
