Every great journey deserves a grand finale—and for the Cassini spacecraft, that ending is just around the corner. In September, it will collide with Saturn’s atmosphere and be destroyed. But in the meantime, it’s scheduled to complete a series of dramatic dives between the planet and its rings. And as Ian O’Neill reports for Space.com, that sequence of daring moves has now begun.
Why dive toward Saturn in the first place? For NASA, it’s a matter not of theatrics, but of science. The craft, which has been on its Saturn journey since 1997, has one last mission: Gather as much data about Saturn as possible in the short period it has left.
Saturn’s rings have long posed intriguing mysteries to scientists. Surrounding the planet in bands, the rings are made of billions of particles of ice and rock that range from from dusty particulate to house-sized hunks. In between the planet and the rings lies a kind of no-man’s land that’s never been explored—until now.
Earlier today, Cassini dropped out of radio contact as it dove between the planet and the rings for the first time. But that doesn’t mean it’s not busy. On its website, NASA notes that the craft will be making maps of Saturn’s gravitational and magnetic fields, detecting potential icy ring particles floating in the in-between region, and snapping photos as it goes. It’s risky business—so it’s worth doing at the end of the craft’s long mission.
O’Neill reports that NASA scientists hope the most valuable science gathered on the entire mission might be found during this series of final orbits. For example, they hope to use the data to figure out the length of a day on Saturn—previously unknown because of the planet’s parallel rotational and magnetic axis. Cassini has already delivered information that changed the way scientists thought about a Saturn day, and more info could be to come.
For now, NASA scientists eagerly wait for the craft to come back into radio contact. These latest dives are just a taste of what will happen on September 15, when Cassini dives into Saturn and goes offline forever. The finale may be bittersweet—but it’s sure to be grand.