Cassini: Saturn probe to set up death plunge

From BBC - September 11, 2017

The international Cassini probe at Saturn will execute the course correction on Monday that will put it on a path to destruction.

The spacecraft is set to fly close to the giant moon Titan - an encounter that will bend its trajectory just enough to send it into the atmosphere of the ringed planet on Friday.

Once the orbit has been tweaked, nothing can stop the death plunge.

Cassini will be torn to pieces within seconds of entering Saturn's gases.

"That final flyby of Titan will put Cassini on an impacting trajectory and there is absolutely no coming out of it," said Earl Maize, the Cassini programme manager at the US space agency (Nasa).

"We are going to go so deep into the atmosphere the spacecraft does not have a chance of coming out."

Ever since it arrived at Saturn 13 years ago, the probe has used the gravity of Titan - the second biggest moon in the Solar System - to slingshot itself into different positions from which to study the planet and its stunning rings.

It has been a smart strategy because Cassini would otherwise have had to fire up its propulsion system and drain its fuel reserves every time it wanted to make a big change in direction.

As it is, those propellants are almost exhausted and Nasa is determined the spacecraft will not be permitted to just drift around Saturn uncontrolled; it must be disposed of properly and fully.

The agency is calling this next Titan encounter the "final kiss goodbye".

It is not actually all that close. The nearest Cassini will get to the moon's surface - timed to occur at 19:04 GMT (20:04 BST; 15:04 EDT; 12:04 PDT) - is about 120,000km. But the nudge this provides will be sufficient to send the mission towards its fiery conclusion at the end of the week.

As the probe passes Titan, it will take one last set of images of this extraordinary world where orange skies produce liquid methane rains that run into huge seas, and where the vast dunes on the moon's surface are made from a plastic-like sand.


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