Cassini to end Saturn’s 20-year mission

WASHINGTON: Nasa’s Cassini spacecraft is about to start a set of “ultra-close” dives through Saturn’s upper atmosphere before a plunge into the planet itself, in a spectacular ending to a nearly 20-year mission.

Following a six-month exploration of previously uncharted areas, its mission is due to end on September 15 as it collides with Saturn’s atmosphere, burning up like a meteor and “becoming part of the planet.”

The last months of Cassini’s mission has seen the craft diving between Saturn’s rings and skirting the outer edge of its atmosphere in a first for any spacecraft. According to Nasa’s website, these last manoeuvres were too risky earlier in the mission because they could damage the spacecraft.

Deputy project scientist Scott Edington said the five final orbits will allow scientists to learn about what Saturn looks like on the inside and get high-resolution images of the rings.

“We’re getting so close to the rings and the planet that we’re starting to see the individual structure of rings,” he said excitedly.

Several years ago scientists realised the spacecraft’s fuel would runout in the near future. They wanted to not only end its mission safely and without disrupting any planets’ or moons’ systems, but also to learn something and to give Cassini an ending with longevity and purpose. The Cassini team decided this Grand Finale was the best way to end the mission.

“The scientific questions you could answer are huge,” Edington said.

It has been a long journey to get to this point. The Cassini spacecraft launched on October 15, 1997, carrying with it the Huygens probe. It took almost seven years to reach the Saturn system.

The Huygens probe was built by the European Space Agency and was designed to travel with Cassini and help explore the Saturn system, Edington said.

Cassini dropped the Huygens probe onto one of Cassini’s moons, Titan, in 2005. This probe helped scientists get an up-close view of Titan. Exploring Titan has been important to scientific study because it is very Earth-like, he said.

“It was our first reveal of the surface,” Edington said. “It definitely provided literally the ground truth of what was happening on Titan.”