What did Nasa learn from Cassini's 20-year mission to Saturn?

Posted September 14, 2017

This Friday evening (15 September) at about 9:54pm AEST, CSIRO's team at the Canberra Deep Space Communication Complex will capture the final signals from NASA's Cassini spacecraft as it plunges into Saturn's atmosphere at over 111,000 kph.

"Cassini-Huygens is an extraordinary mission of discovery that has revolutionised our understanding of the outer solar system", said Alexander Hayes, assistant professor of astronomy at Cornell University.

Before contact is lost, eight of Cassini's 12 scientific instruments will be operating. "In fact, you can think of Cassini becoming the first Saturn probe". "Death Dive to Saturn" joins last month's NOVA episode on the total eclipse, "Eclipse Across America", and the PBS presentation of the independent documentary on another space probe, "The Farthest - Voyager in Space" (streaming online September 14-27). They do not want any earthly organisms that may be on Cassini to contaminate a moon that may have life.

What was the objective of the mission? There was particular interest in Saturn's biggest moon Titan, which in some ways resembles an early version of Earth. "And then to take instruments built for other purposes and turn them toward sampling and flying through the plumes and actually measuring the constituents - finding a salty global ocean containing organics, the possibility of hydrothermal ventsand just revealing a world that we thought was completely frozen solid when we first got to Saturn". Then, 17 years later, in October 1997, a much more powerful mission was launched: Cassini-Huygens.

Each fly-by provided a gravitational "kick" that boosted Cassini's speed to more than 42,500mph and helped the probe on its way.

What discoveries has it made?

The pioneering space probe will leave no trace, keeping the surface of Saturn and its moons pristine for future exploration.

The spacecraft also investigated giant storms on Saturn and spotted raging hurricanes at both poles. The Cassini mission has given us answers to a lot of the outstanding questions that we had about this atmosphere - showing it to be similar to our own, with temperatures and pressures at Titan's surface meaning that methane can condense to a point where it creates clouds, and falls as rain.

What did Huygens learn about Titan?

"We're still open to trying to look for weird life in places like this and we found a unusual place right here in our solar system", Cable said. Thanks to Cassini, NASA now knows that some of Saturn's planetary worlds hide liquid water and may have the potential to support life. So instead, Cassini was powered by a small plutonium-fuelled nuclear reactor. Now, the spacecraft is gearing up for a crash landing on the planet that it observed so thoroughly, as it flew past Titan one final time for a gravity assist that NASA called a final kiss goodbye. It's due to finish off its Grand Finale with a fatal plunge into Saturn, destroying itself just a month shy of the 20-year anniversary of its launch. Named after the 17th-century Dutch astronomer who discovered Titan, Christiaan Huygens, Huygens was a project of the European Space Agency (ESA) which landed on Titan on January 14, 2005, sending data back to Earth for 90 minutes.