NASA's Cassini spacecraft has marked its final close pass of the Saturnian moon Dione by capturing the rocky body in a series of stunning images as it sailed past the satellite on August, 17. Cassini had previously visited the moon five times, but had never before captured the moon in so high a resolution.

Dione is a relatively small Saturnian moon orbiting roughly 234,000 miles (377,400 km) out from the gas giant. With a density only 1.48 times that of liquid water, the moon's surface is characterized by heavy cratering, with some of the scars spanning over 60 miles (97 km) in diameter.

Cassini's latest flyby took the spacecraft to within 295 miles (474 km) of the moon on Aug. 17, capturing a series of brooding images with both its wide and narrow angle cameras. The images returned by Cassini were a mere accompaniment to its primary goal of seeking clues to the moon's interior structure as part of a gravity science experiment, the data from which will be pored over by mission scientists in the months to come.

Nine clear spectral filter images were combined to create this mosaic of Dione(Credit: NASA/JPL-Caltech/Space Science Institute)

Two of the latest Cassini shots represent the highest resolution images ever captured of Dione's barren surface, whilst others show the moon at a distance, with Saturn and her rings looming large in the background. Regardless of the composition, each of the shots are framed in the knowledge that Cassini will never pass this close to Dione again, transforming the images into a forlorn farewell from the veteran spacecraft.

"I am moved, as I know everyone else is, looking at these exquisite images of Dione's surface and crescent, and knowing that they are the last we will see of this far-off world for a very long time to come," states Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Colorado. "Right down to the last, Cassini has faithfully delivered another extraordinary set of riches. How lucky we have been."

Dione imaged by Cassini at a distance of 45,000 miles (73,000 km) with Saturn in the background(Credit: NASA/JPL-Caltech/Space Science Institute)

Cassini may have left Dione for good, but the little probe is far from done. Prior to the crescendo of its final year, during which the orbiter will pass repeatedy between Saturn and its iconic ring system, Cassini will pass within 30,000 miles (50,000 km) of some of the gas giant's largest moons, and will get closer to some of the smaller irregular bodies orbiting the pale planet than ever before.

Nearly 18 years after its launch atop a Titan IVB/ Centaur rocket, and having traveled a mind-boggling distance in pursuit of its scientific objectives, the old boy still has some sights to show us.

Source: NASA JPL

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