THE CASSINI spacecraft embarked on its cosmic journey across our solar system two decades ago. After 4.9 billion miles of travel, the mission came to an end early Friday morning in a bittersweet finale as the orbiter ran out of fuel and crashed into Saturn's atmosphere. Its planned demise represents the end of an era for a generation of space researchers, but it also marks a profound accomplishment for humanity and science.
During the course of its voyage, the Cassini space probe visited three of our neighboring planets, discovered six new moons and beamed back thousands of stunning photos to its home planet. It captured not only the inherent human spirit of exploration — traveling more than 100,000 times the distance of Ferdinand Magellan's expedition to circumnavigate the globe — but also the imagination of millions of people. Across this globe it kindled scientific inquiry in the minds of young people.
In many ways, the Cassini mission embodies the best of our species. Twenty-seven nations poured resources into the voyage — not for the sake of conquest, but for the pursuit of knowledge. After depositing its Huygens probe into the hazy Saturn moon of Titan, Cassini discovered seas of liquid methane. And while diving into the icy plumes of Enceladus, it discovered a frigid, yet active world complete with organic compounds — the building blocks of life on Earth.
Could it be that moons in the Saturnian system harbor microbial neighbors — the first evidence of life elsewhere in the universe? We do not yet know, but the discoveries tug on humanity's adventurous spirit. This is more than just curiosity, it is hope for a greater understanding about life.
Humans have now sent robotic representatives to visit each of our solar system's planets and the dwarf planet Pluto. Upon arrival, we have discovered new moons and mind-blowing geological features that humble those found in our own world. We have even landed a spacecraft on a comet.
Human ingenuity has advanced by incredible lengths since men first landed on the moon in 1969. But Cassini's obituary should not also mark the end of human exploration — far from it. Just like other missions that have come to an end, Cassini's journey offers a mandate for more: in this case, to return to Saturn and continue the search for life beyond Earth.
Scientists and engineers at NASA, the Jet Propulsion Laboratory at the California Institute of Technology and elsewhere who worked on the Cassini mission should be commended for their decades-long work. People across the globe will see the images and read about their discoveries for generations. Cassini's retirement deserves not only a fond farewell, but also proud applause for its contribution to science.