Cassini read­ies for fi­nal plunge

Satel­lite to trans­mit data on Saturn un­til it burns up

Global Times - - World -

The US space agency’s Cassini space­craft will end its 13- year mis­sion to Saturn in mid- Septem­ber by trans­mit­ting data un­til the fi­nal mo­ment be­fore it plunges into the at­mos­phere, of­fi­cials said on Tues­day.

Cassini, the first space­craft to or­bit Saturn, will make the last of 22 farewell dives be­tween the planet’s rings and sur­face on Septem­ber 15. The space­craft will then burn up as it heads straight into the gas gi­ant’s crush­ing at­mos­phere.

Cassini’s fi­nal dive will end a mis­sion that pro­vided ground­break­ing dis­cov­er­ies that in­cluded sea­sonal changes on Saturn, the moon Ti­tan’s re­sem­blance to a pri­mor­dial Earth, and a global ocean on the moon Ence­ladus with ice plumes spout­ing from its sur­face.

“The mis­sion has been in­sanely, wildly, beau­ti­fully suc­cess­ful, and it’s com­ing to an end in about two weeks,” Curt Niebur, Cassini pro­gram sci­en­tist, said on a tele­phone con­fer­ence call with re­porters from NASA’s Jet Propul­sion Lab­o­ra­tory in Cal­i­for­nia.

Cassini’s fi­nal photo as it heads into Saturn’s at­mos­phere will likely be of pro­pel­lers, or gaps in the rings caused by moon­lets, said project sci­en­tist Linda Spilker.

The space­craft will pro­vide near real- time data on the at­mos­phere un­til it loses con­tact with Earth at 4: 54 a. m. PDT ( 1154 GMT) on Septem­ber 15, the Na­tional Aero­nau­tics and Space Ad­min­is­tra­tion said.

Spilker said Cassini’s lat­est data on the rings had shown they had a lighter mass than fore­cast. That sug­gests they are younger than ex­pected, at about 120 mil­lion years, and thus were cre­ated af­ter the birth of the so­lar sys­tem, she said.

Dur­ing its fi­nal or­bits be­tween the at­mos­phere and the rings, Cassini also stud­ied Saturn’s at­mos­phere and took mea­sure­ments to de­ter­mine the size of the planet’s rocky core. Cassini has been prob­ing Saturn and its 62 known moons since July 2004. It has pro­vided enough data for al­most 4,000 sci­en­tific pa­pers.

Since the craft is run­ning low on fuel, NASA is crash­ing it into Saturn to avoid any chance Cassini could some­day col­lide with Ti­tan, Ence­ladus or any other moon that has the po­ten­tial to sup­port in­dige­nous mi­cro­bial life.

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