Cassini has fulfilled dozens of objectives. But a couple have eluded it. One is that we still don’t know how long a day is on Saturn because we aren’t quite sure about the structure of its magnetic field. The other is that we don’t know the true mass of the rings. It’s hoped these Grand Finale orbits may provide some answers.
The mission has continuously required innovations, as Cassini could only carry 12 instruments. One that's rather incredible is that mission scientists used Saturn’s rings to study the planet’s interior. Looking at patterns within the rings, and monitoring movement within them, it’s been possible to describe movements taking place within Saturn.
Just because the Cassini mission is coming to a close, however, it does not mean the mission is over. Once the mission ends on September 15, scientists will spend another year archiving all the remaining data from the mission. It could then be decades before researchers have finished publishing papers from this data. There’s a long way to go.
Understandably, though, the end of this groundbreaking mission is a heartfelt occasion. “It’s hard to see something that is such a huge part of your life come to an end,” said Ray, who has worked on the mission for 21 years. “It’s like a neighborhood. People have gotten married and had kids, and they have gone to college. And all the big surprises from Cassini are done. It’s a sad time. It’s bittersweet.”
Cassini’s demise leaves just one spacecraft orbiting a planet in the outer Solar System – NASA’s Juno spacecraft around Jupiter. No other spacecraft to this region is currently in the works, although there are numerous ideas.
With attention seeming to focus on the Moon and Mars at the moment, it’s vital to remember how important and groundbreaking planetary science is. Cassini’s end should not be mourned but celebrated, a reminder of how a little cooperation can reap a huge reward. Wherever we go next, Cassini will be a benchmark every other mission can only dream of matching.