NASA’s Cassini spacecraft is about to complete its 20-year mission in dramatic fashion.
After a seven-year flight to Saturn and 13 years orbiting the second largest planet in the solar system, Cassini is ready to take the plunge—down Saturn’s gravity well and into the planet’s slushy surface.
“In so many ways the grand finale is like a brand new mission,” said Cassini project scientist Linda Spilker. “We’re going to a place and obtaining data with the Cassini spacecraft we could only obtain and doing it this way.”
For the next two weeks the spacecraft will make a series of dives into the gap between the planet and its rings. Cassini will get precise measurements of the mass of the rings, which will help determine their age, and will also analyze their substance.
“[The] Other thing we can do for the first time is determine the composition of the ring particles. Now we know that Saturn’s rings are 99 percent water ice but we’re not certain about that other 1 percent non-icy constituent. What is it made of?” asked project scientist Linda Spilker.
“Could it be tiny grains of iron, silicates, organics a mix of all three? Something else we haven’t even thought of? When our cosmic dust analyzer goes through the ring plane it will scoop up ring particles and directly taste and measure the composition of those particles,” she said.
Finally, on April 26, Cassini will plunge directly into the planet, sending back information about the planet’s composition and structure until gravity crushes it.
“I wouldn’t be a bit surprised if some of the discoveries we make with Cassini might be the very best of the mission from these grand finale orbits,” Spilker concluded.