NASA’s Cassini plans fi­nal fiery en­counter with Saturn.

The Washington Times Daily - - FRONT PAGE - BY MAR­CIA DUNN

CAPE CANAVERAL, FLA. | Af­ter a 20-year voy­age, NASA’s Cassini space­craft is poised to dive into Saturn this week to be­come for­ever one with the ex­quis­ite planet.

There’s no turn­ing back: Fri­day, it ca­reens through the at­mos­phere and burns up like a me­teor in the sky over Saturn.

NASA is hop­ing for sci­en­tific div­i­dends up un­til the end. Ev­ery tid­bit of data ra­dioed back from Cassini will help as­tronomers bet­ter un­der­stand the en­tire Satur­nian sys­tem — rings, moons and all.

The only space­craft ever to or­bit Saturn, Cassini spent the past five months ex­plor­ing the un­charted ter­ri­tory be­tween the gaseous planet and its daz­zling rings. It’s darted 22 times be­tween that gap, send­ing back ever more won­drous pho­tos.

On Mon­day, Cassini flew past jumbo moon Ti­tan one last time for a grav­ity as­sist — a fi­nal good­bye kiss, as NASA calls it, nudg­ing the space­craft into a de­lib­er­ate, no-way-out path.

Dur­ing its fi­nal plunge early Fri­day morn­ing, Cassini will keep sam­pling Saturn’s at­mos­phere and beam­ing back data, un­til the space­craft loses con­trol and its an­tenna no longer points to­ward Earth. Descend­ing at a scorch­ing 76,000 mph, Cassini will melt and then va­por­ize. It should be all over in a minute.

“The mis­sion has been in­sanely, wildly, beau­ti­fully suc­cess­ful, and it’s com­ing to an end,” said NASA program sci­en­tist Curt Niebur. “I find great com­fort in the fact that Cassini will con­tinue teach­ing us up to the very last sec­ond.”

Tele­scopes on Earth will watch for Cassini’s burnout nearly a bil­lion miles away. But any flashes will be hard to see given the time — close to high noon at Saturn — and Cassini’s mi­nus­cule size against the so­lar sys­tem’s sec­ond largest planet.

The whole point of this one last ex­er­cise — dubbed the Grand Fi­nale — is to pre­vent the space­craft, launched in 1997, from crash­ing into the moons of Ence­ladus or Ti­tan. NASA wants fu­ture ro­botic ex­plor­ers to find pris­tine worlds where life might pos­si­bly ex­ist, free of con­tam­i­na­tion from Earth.

It’s in­evitable that the $3.9 bil­lion U.S.-Euro­pean mis­sion is wind­ing down. Cassini’s fuel tank is al­most empty, and its ob­jec­tives have been ac­com­plished many times over since its 2004 ar­rival at Saturn fol­low­ing a seven-year jour­ney.

The leader of Cassini’s imag­ing team, plan­e­tary sci­en­tist Carolyn Porco, al­ready feels the loss.

“There’s an­other part of me that’s just, ‘It’s time. We did it.’ Cassini was so pro­foundly, sci­en­tif­i­cally suc­cess­ful,” said Ms. Porco, a vis­it­ing scholar at the Univer­sity of Cal­i­for­nia, Berke­ley. “It’s amaz­ing to me even, what we were able to do right up un­til the end.”

Un­til Cassini, only three space­craft had ven­tured into Saturn’s neigh­bor­hood: NASA’s Pi­o­neer 11 in 1979 and Voy­ager 1 and 2 in the early 1980s. Those were just fly­bys, though, and of­fered fleet­ing glances. And so Cassini and its trav­el­ing com­pan­ion, the Huy­gens lan­der, ac­tu­ally pro­vided the first hard look at Saturn, its rings and moons. They are named for 17th-cen­tury as­tronomers, Ital­ian Gio­vanni Domenico Cassini and Dutch Chris­ti­aan Huy­gens, who spot­ted Ti­tan, the first of Saturn’s 62 known moons.

All told, Cassini has trav­eled 4.9 bil­lion miles since launch, or­bited Saturn nearly 300 times and col­lected more than 453,000 pic­tures and 635 gi­ga­bytes of sci­en­tific data.

AS­SO­CI­ATED PRESS

On Fri­day, NASA’s Cassini space­craft will ca­reens through the at­mos­phere and burn-up like a me­teor over Saturn. NASA hopes for sci­en­tific div­i­dends.

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