At 4:55 am PST, Cassini sent its final message before plunging into Saturn’s atmosphere, breaking up, and falling to Saturn’s surface. During its twenty-year-long mission, Cassini helped scientists gain significant insight on Saturn.
After the two Voyager spacecraft flew past Saturn in 1982, scientists from around the globe planned what we now call Cassini. Following take off in 1997, Cassini arrived at Saturn 7 years later, ready to conduct research on the planet and its moons. During its lifetime, the spacecraft completed 127 flybys of Titan, 23 flybys of Enceladus, and 15 flybys of Saturn’s icy satellites. These targeted missions have helped reveal the possibilities of life on Titan and Enceladus.
When Voyager snapped blurry photos of Titan’s hazy, largely Nitrogen-based atmosphere, scientists were captivated by this moon. Nitrogen comprises much of Earth’s atmosphere, and this discovery hinted at possibilities of life on Titan. German scientists designed the Huygens probe to accompany Cassini and to pass through Titan’s atmosphere while gathering data during its dive and on the moon’s surface. Photos from Huygens displayed Titan’s striking similarities to Mars, and allowed scientists to map the surface of Titan, which includes huge lakes filled with a mixture of liquid methane and ethane. Both the Voyager and now Huygens helped make tremendous strides about the prospect of life on Titan.
Enceladus had long been considered a dead moon before Cassini’s mission. Enceladus’s icy surface was recognized as the brightest in the solar system. Cassini noticed that this moon has a surface full of craters , almost all of them covering the north pole. After noticing this oddity, Cassini’s instruments further revealed that the south pole contained huge plumes of water vapor and organic materials shooting up from under the surface. Measurements from Cassini suggested a large sea 6 miles deep underneath an ice shell (Enceladus’ surface) 19-25 miles thick. Heat emanating from the cracks in the ice also hint at hydrothermal vents, just like those in Earth’s oceans. Many organisms thrive near the hydrothermal vents on Earth, an exciting prospect if the water on Enceladus mirrors that on Earth.
The last of Cassini’s major achievements: the spacecraft captured fascinating videos of the massive hurricane at Saturn’s north pole called “the Hexagon” and documented how its color changes based on the seasons. Thanks to Cassini, scientists have discovered propellor-shaped gaps in the ring material of the A ring (the outermost denser ring). These gaps are moonlets, smaller than known moons and look like they are in the initial (but stunted) stages of planet development. These “propellor belts” present an image of what the Solar System could have looked like during its formation. Cassini may have just taken its final loops between Saturn’s rings and Saturn’s surface in its grand finale, but the information uncovered due to Cassini will help researchers for decades to come, including the continuing search for life away from Earth.