NASA's Cassini completes 'goodbye kiss' and turns to face its fiery death

NASA's Cassini completes 'goodbye kiss' and turns to face its fiery death

The final plunge took place on the day side of Saturn, near local noon, with the spacecraft entering the atmosphere around 10 degrees north latitude. The probe spent 20 years in space - the last 13 years it orbited around Saturn.

The Cassini mission has been a fantastic worldwide achievement made possible via NASA and the European Space Agency (ESA). Powered by plutonium (which led to some protests when the probe launched in 1997), the $3.9 billion spacecraft slingshotted around Venus twice and Earth once before traveling on to Jupiter to accelerate enough to reach Saturn in 2004.

Having expended nearly all of the rocket propellant it carried to Saturn, NASA said Cassini was intentionally put on a path to plunge into the gas giant to ensure Saturn's moons - in particular the ice-covered, ocean-bearing moon Enceladus, with its subsurface ocean and signs of hydrothermal activity - remained pristine for future exploration.

The craft travelled almost 5 million miles since its launch from Cape Canaveral in Florida back in 1997. Perhaps Cassini's biggest revelation was the fact that Enceladus has a global ocean underneath its crust, one that could be habitable. It was during these flybys that the most detailed true color photos of the gas giant ever recorded were beamed back to Earth.

Full disclosure: I did not expect to feel an emotional impact from Cassini's dive into Saturn.

For Zadie, age 8, it was her first-ever glimpse of Saturn. These include Methone, Pallene, Polydeuces, Daphnis, Anthe and Aegaeon.

Possel said that, for him, a highlight of the mission was the discovery of water on Saturn's moon Enceladus. Those missions may pave the way for a lander on Europa (SN Online: 2/18/17), which could directly look for life in that moon's subsurface seas.

Goodbye to Enceladus. Image: NASA.

"Cassini may be gone, but its scientific bounty will keep us occupied for many years", Linda Spilker, Cassini project scientist said in the release. "If life is eventually discovered in Enceladus' ocean by a mission after Cassini, then our Enceladus discoveries will have been among the top discoveries for all planetary missions".

At 9:56 pm AEST time, radio contact with the 22ft-long nuclear-powered probe was lost as it tumbled to its demise 930 miles above the cloud tops of the planet. Many generations of physicists, astronomers and astrobiologists are going to be fascinated by Saturn because of Cassini.

Cassini reported its final data early Friday morning.

After a last flyby of the Saturn's moon Titan, the spacecraft dived between Saturn's uppermost atmosphere and its innermost ring 22 times. It gathered more than 635 gigabytes of science data and took more than 450,000 images.

Still, all good things must end, and NASA's mission statement is "to pioneer the future in space exploration".

Late past year, the Cassini spacecraft executed a daring set of ring-grazing orbits.

Saturn's atmosphere crushed and melted the bits and pieces, until they completely dissociated and became part of the very planet the spacecraft had been sent to observe.

After a 20-year flight, Cassini was running out of fuel, so NASA made a decision to crash Cassini before letting it remain aloft, where it could have been knocked into Titan, the moon with methane lakes, or Enceladus, the moon with jets of water in its southern pole. Among the attendees, Julie Webster, the spacecraft's operations manager, had worked with Cassini since its invention.