Seeing Saturn: An amazing milestone

Published Sep 23, 2017 at 4:00pm

Twenty years ago, the Cassini-Huygens spacecraft began its 4.9 billion-mile odyssey to Saturn with a picture-perfect liftoff. The $3.9 billion mission -- a three-way collaboration among NASA, the Italian Space Agency and the European Space Agency -- was ambitious by the standards of any age. Saturn, with its dozens of moons that have fascinated astronomers since the 17th century, was ready for a nearly two-decadelong close-up.

When the Cassini-Huygens spacecraft arrived in 2004, it quickly discovered that Saturn’s neighborhood was much bigger and denser than expected. There are at least 69 moons we are now aware of, thanks to Cassini snooping around, but there are probably more to be discovered.

For 13 years, Cassini has been orbiting what is arguably the most beautiful planet that isn’t Earth in our solar system. It has photographed Saturn thousands of times from various angles. It has also documented the thickness and weirdness of its multiple rings and cataloged its moons from afar.

Early in the mission, the Huygens lander separated from the Cassini orbiter and lit off for the hydrocarbon wilderness of Titan, Saturn’s largest and most fascinating moon.

In doing so, Huygens became the first spacecraft to land on a moon other than our own. That in itself became an impressive technological feat that got lost in the relentless successes of the overall mission.

While a close-up look at Titan with its frozen lakes and rivers was expected to be one of many highlights of the mission, what absolutely blew scientists away was discovering the water and snow-like plumes jetting up miles from the surface of the moon Enceladus. That was not expected when the mission was put together.

Cassini flew through the snow and ice plumes during it s many drive-bys of the moon, but it isn’t carrying technology designed to detect and analyze microbial life if it is present. That will have to wait for another mission.

As for Cassini itself, all good things must come to an end. The 4,685-pound probe rapidly descended through the rings and deeper into the planet’s gravitational clutches. Cassini has made the vastness of our solar system a little more intimate. As a species, we are so much more enriched by the Cassini-Huygens mission. Future missions will do even more, but that doesn’t detract from Cassini’s monumental achievement.