By Aryan Wani

The plethora of graphic novels and astrological textbooks that we used to consume as a child has led us to believe that a lot is known about our universe; what with millions upon millions of visually stimulating images related to planets and collapsing nebulas readily available all over the internet. However, the true intricacy of the gas giants in our solar system alone is underappreciated – with so much more to learn. The Cassini mission is ‘one giant leap for mankind’ in comprehending the nature of Saturn – a giant ball of gas; but the word ‘giant’ is relative – in this case, we are talking the size of 764 Earths.

Cassini was the first spacecraft to orbit Saturn as the mission began the most detailed, first-hand study of Saturn and its system of rings and moons from 2004 to 2010.

Cassini's observations of Saturn's largest moon, Titan, have given scientists a glimpse of what Earth might have been like before life evolved. They now believe Titan possesses many parallels to Earth, including lakes, rivers, channels, dunes, rain, clouds, mountains and possibly volcanoes.

Spray of ice particles from the surface of Enceladus

Spray of ice particles from the surface of Enceladus

Enceladus, too, proved to be a rich source of discovery, with extremities in the climate observed for the first time. A spray of icy particles from the surface jets of the moon forms a towering plume three times taller than the width of Enceladus itself. The plume directly feeds particles into Saturn's most expansive ring, the E ring. The spacecraft came a startling 25 kilometres close to the moon's icy surface during its investigation, revealing the presence of a global subsurface ocean that might have conditions suitable for life. To put this unimaginably small distance in perspective, even weather balloons can rise to an altitude of 39 kilometres above the surface – hence coming so close to the surface is ground-breaking in its own right.

In 2010, the spacecraft began a second, seven-year-long, extended mission called the Cassini Solstice Mission.

Artistic depiction of the Grand Finale

Artistic depiction of the Grand Finale

To its very end, Cassini was unarguably a mission of thrilling exploration. In April 2017, NASA's Cassini spacecraft began the final chapter of its 20-year-long story of exploration: The Grand Finale. Every week, Cassini dived through the approximately 1,200-mile-wide gap between Saturn and its rings. This final mission concluded with a phase including 22 deep dives between Saturn's cloud tops and innermost ring before it plunged into the giant planet's atmosphere. No other spacecraft had ever explored this unique region.

A final close flyby of the moon Titan on April 22 used the moon's gravity to reshape Cassini's trajectory so that the spacecraft leapt over the planet's icy rings to pass between the rings and Saturn. At times, Cassini passed by the very inner edge of the rings – while other times, it passed by the outer edges of the atmosphere. During its final five orbits, it passed through Saturn's uppermost atmosphere, before finally plunging directly into the planet on Sept. 15 like a meteor, ending Cassini’s mission.