Nasa is going to fly a spacecraft to its own fiery death on Saturn.
The spectacular final act of the Cassini spacecraft will help ensure that humanity doesn’t accidentally infect other parts of the solar system with aliens carried there from Earth.
Cassini arrived at Saturn in July 2004, and since then has been exploring the giant planet and the 62 known moons that surround it. That includes Titan, which looks like the early Earth, and Enceladus, which has an ocean, spurts ice particles out into space, and has been mentioned as a candidate for having life.
To ensure that the Cassini craft doesn't accidentally land on one of those moons and take with it some living organisms that could infest it, Nasa will crash the spacecraft into Saturn. As it does so, it wll burn up and get rid of any hitchhikers.
But before its demise, Cassini has one last mission. On April 22, Cassini will make a final pass by Titan and use the moon's gravity to slingshot itself into a new orbit that passes inside the 1,200-mile-wide gap between the edge of Saturn’s atmosphere and its inner-most rings.
Nasa is hoping Cassini will survive long enough for 22 dives inside the rings, revealing details about the their age and composition. But if a ring particle hits Cassini, it could bring the mission to an premature end because the spacecraft will be travelling at more than 70,000 miles per hour (112,654 kph).
“At those speeds, even a tiny particle can do damage,” Cassini flight engineer Joan Stupik, with Nasa’s Jet Propulsion Laboratory in Pasadena, California, told reporters during a news conference on Nasa TV.
Scientists hope to learn if the rings are as old as Saturn itself – roughly 4.6 billion years of age – or if they formed later after a passing comet or moon was shredded by the planet’s tremendous gravity.
During the close ring encounters, Cassini also will study Saturn’s atmosphere and take measurements to determine the size of the rocky core believed to exist at the centre of the gigantic ball of gas that accounts for most of its size.
However long Cassini lasts, “the grand finale will be spectacular,” said project scientist Linda Spilker, also with the Jet Propulsion Laboratory.
“We’re flying in a region that has never been explored before,” she said. “I wouldn't be a bit surprised if some of the discoveries we make with Cassini during the grand finale are the best of the mission.”
Additional reporting by Reuters
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