In the early hours of September 15 (EDT), the Cassini probe will break apart and burn up in Saturn’s atmosphere.

Launched in October of 1997, it entered orbit around the ringed giant on July 1, 2004. A complex dance amongst the moons and rings revealed many surprises. The moon Enceladus has an ocean of water under its icy shell. Titan has lakes of methane, and an atmosphere of hydrocarbons that contains complex molecules that just might be able to combine into lifelike assemblages. The rings are a far more dynamic and interesting place than we imagined.

http://www.nationalgeographic.com/science/2017/09/cassini-saturn-nasa-3d-grand-tour/#preamble

The probe is deliberately being destroyed so as to avoid possible contamination of Enceladus and Titan.

It’s a bittersweet ending for the scientists on the program, many of whom were there from the planning stages in the 1980s.

“It’s been part of my life for so long, this spacecraft, it’s going to be a shock to have this happen,” said Thomas Burk, a JPL engineer. Linda Spilker, a Cassini project scientist, said, “Our families have gotten to know each other, in some cases our children have grown up together, and now in the final two weeks we’re sharing the end of this incredible mission.”

By the time you read this, Cassini will have passed the “point of no return”, taken its final photographs, and sent its collected store of data back home. About 12 hours after that, the onboard computers will have reconfigured for real-time data transmission. It will attempt to send back information on temperature and the composition of the atmosphere for as long as it can. But eventually, there won’t be any fuel left to stabilize the craft as it shudders and tumbles in the upper atmosphere. Cassini will heat up; parts of it will break off. The main body of the craft will explode. As NASA spokesperson Preston Dyches has said, “We’re going out in a blaze of glory.”

The next big planetary science effort is the Europa Clipper, which will launch in the 2020s. Its goal is to investigate Jupiter’s ice moon. There’s nothing else in the works for the outer solar system. Given that it takes about a decade of planning just to get a mission off the ground (literally), trips to the outer Solar System are for the next generations to enjoy.

Yes, we all know there are more important things to spend our money on here on Earth. And we’re not giving up on Mars at all. But it’s still a sad sign to know that an era of exploration is coming to an end, with no plans at all to return to those farthest shores.