But nothing lasts forever. The scientists could have left Cassini for dead when its time came, a derelict in space. But that would have risked contamination on Saturn’s pristine and now very interesting moons, should the spacecraft hit them. So it had to go, and anyway there was still more to be learned by crashing it into Saturn.
Cassini’s fate was sealed last April. Using Titan’s gravitational pull, Cassini changed course oh so slightly onto a trajectory that would take it on the first of 22 passes inside Saturn’s rings, where no spacecraft has ever gone.
On September 11, Cassini will get one more “goodbye kiss” from Titan, a last fatal gravitational nudge directing the spacecraft into Saturn itself.
The cameras will turn off on the 14th, after one final look around the environs Cassini has called home for the last 13 years. But most of the spacecraft’s instruments will keep working, gathering and analyzing samples of the planet’s atmosphere as the spacecraft blazes into the clouds, which should tell us something about how the giant planet formed and evolved. Have the rings always been there, or are they a more (cosmically) recent addition?
Scientists and the press, in all its social media glory, will assemble at the Jet Propulsion Laboratory to witness the demise of Cassini, estimated to happen on September 15 at about 7:54 a.m. Eastern Daylight Time. Last week Cassini sent back what Carolyn Porco, of the Space Science Institute in Boulder, Colo., and imaging team leader on the project, called “one of our last best looks at Enceladus…that small moon at Saturn with the big possibilities.”
“Brace yourselves,” she added in an email. “The end is near.”
The news for all those gathered will arrive as a sudden silence. Cassini will break up and burn like a meteor into a wisp of stray atoms lost in the clouds. Dr. Porco said that the entry point would be visible from Earth and that some amateur astronomers were hoping to see some sign of Cassini’s entry.
But the odds are against them. And so Cassini will wave goodbye with a flash of unearthly light that no humans, at least, may ever see.