Saturn: the jewel of our solar system. Wheeling in its lonely orbit around the Sun, the sheer magnificence of the gas giant and its rings have fascinated observers on Earth since the time of Galileo. However, for centuries Saturn remained largely shrouded in mystery, a point of light in the night sky harboring secrets about a beautiful, unknown world.
This all changed with Cassini. The Cassini-Huygens mission is a joint NASA/European Space Agency/Italian Space Agency mission to explore Saturn and its moons. Pioneer 11 and Voyagers 1 and 2 had previously conducted flybys of Saturn, but Cassini is the first spacecraft to orbit Saturn and provide an in-depth look at the Saturnian system. Over the course of its mission, Cassini has collected a wealth of data about Saturn and its rings and moons, and has shed enormous light on the mysterious gas giant.
What is Cassini? The mission has two elements: the Cassini orbiter to explore Saturn, and the Huygens probe to explore one of Saturn’s moons, Titan, which provides a glimpse of what Earth might have looked like before the evolution of life. The Cassini spacecraft, carrying the Huygens probe, was launched on October 15, 1997; it reached Saturn on June 30, 2004. Cassini entered Saturn’s orbit, while the Huygens probe continued on to Titan, which it reached in January of 2005. The probe, carrying six scientific instruments, performed a 2.5 hour descent through Titan’s dense atmosphere before landing on Titan’s surface—the most distant spacecraft landing to date. Huygens collected and beamed back to Earth valuable data about Titan’s atmosphere, including electromagnetic properties, chemical makeup, and wind speed; these data have revealed that Titan undergoes many Earth-like processes.
The mission has two elements: the Cassini orbiter to explore Saturn, and the Huygens probe to explore one of Saturn’s moons, Titan.
The Cassini orbiter has on board twelve instruments with various functions, including measuring magnetic fields, electric charges, and atomic particles, investigating plasma waves, and characterizing Saturn’s atmosphere and magnetosphere. It also has a powerful imaging system that can take detailed images in a wide range of light spectra, from the infrared to the ultraviolet, which has yielded breathtaking images of Saturn in stunning detail . From the data collected by Cassini, scientists have made numerous remarkable discoveries about Saturn, its ring system, and its dynamic moons, including the discovery that Saturn’s moon Enceladus spews out plumes of ice and water vapor and harbors an ocean of liquid water beneath its icy surface.
Cassini will continue contributing to scientific discovery until the very end. As it performs its final series of daring dives between Saturn and its rings, it will collect valuable data that was too risky to obtain earlier, including information about the composition of the rings that will help us understand their origins. Cassini will also have the opportunity to take incredible, close-up images of Saturn’s rings and clouds. Cassini successfully completed its first dive through the gap on April 26, 2017 and emerged in excellent shape; the next dive is scheduled for May 2. It will complete a total of 22 dives before burning up in Saturn’s atmosphere on September 15, 2017, becoming a part of the planet that it has explored for 13 years. It is a bittersweet conclusion to a scientifically-rich journey that has inspired our wonder, enhanced our understanding of the solar system, and pushed the boundaries of human exploration.