NASA has released a series of breathtaking images of Enceladus, a frozen moon of Saturn, captured by the agency’s Cassini spacecraft.
Cassini captured this image of Enceladus as it neared the moon for its closest-ever dive past the moon’s active south polar region. The image was taken in visible light with the spacecraft’s narrow-angle camera on October 28, 2015. The image shows heavily cratered northern latitudes at top, transitioning to fractured, wrinkled terrain in the middle and southern latitudes. The wavy boundary of the moon’s active south polar region is visible at bottom, where it disappears into wintry darkness. This view looks towards the Saturn-facing side of Enceladus. The image was taken at a distance of approximately 60,000 miles (96,000 km) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 45 degrees. Image credit: NASA / JPL-Caltech / Space Science Institute.
On October 28, at approximately 11:22 a.m. EDT (8:22 a.m. PDT), Cassini made the deepest dive ever through the plume of Enceladus, skimming about 30 miles (49 km) above the moon’s south polar region.
“Cassini’s stunning images are providing us a quick look at Enceladus from this ultra-close flyby, but some of the most exciting science is yet to come,” said Dr Linda Spilker of NASA’s Jet Propulsion Laboratory.
This artist’s rendering showing a cutaway view into the interior of Enceladus. A plume of ice particles, water vapor and organic molecules sprays from fractures in the moon’s south polar region. Image credit: NASA / JPL-Caltech.
Cassini scientists will soon begin studying data from the spacecraft’s gas analyzer and dust detector, which directly sampled the moon’s plume of gas and dust-sized icy particles during the flyby.
Those analyses are likely to take few weeks, but should provide important insights about Enceladus’ global ocean.
The researchers are hopeful the flyby will provide insights about how much hydrothermal activity – that is, chemistry involving rock and hot water – is occurring within Enceladus.
This image of Enceladus was acquired by NASA’s Cassini spacecraft during a close flyby of the icy moon on October 28, 2015. Image credit: NASA / JPL-Caltech / Space Science Institute.
“This activity could have important implications for the potential habitability of the ocean for simple forms of life,” they explained.
“The critical measurement for these questions is the detection of molecular hydrogen by the spacecraft.”
They also expect to better understand the chemistry of the Enceladus’ plume as a result of the flyby.
This image from Cassini shows the south polar region of Enceladus. The wavy boundary of the moon’s south polar region is visible at bottom, where it disappears into wintry darkness. The image was taken at a distance of approximately 38,000 miles (61,000 km) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 42 degrees. Image credit: NASA / JPL-Caltech / Space Science Institute.
“The low altitude of the encounter is, in part, intended to afford Cassini greater sensitivity to heavier, more massive molecules, including organics, than the spacecraft has observed during previous, higher-altitude passes through the plume,” the scientists said.
“The flyby will help solve the mystery of whether the plume is composed of column-like, individual jets, or sinuous, icy curtain eruptions – or a combination of both. The answer would make clearer how material is getting to the surface from the ocean below.”
During its closest ever dive past the active south polar region of Enceladus, Cassini quickly shuttered its imaging cameras to capture glimpses of the fast moving terrain below. This view has been processed to remove slight smearing present in the original, unprocessed image that was caused by the spacecraft’s fast motion. This view is centered on terrain at 57 degrees south latitude, 324 degrees west longitude. The image was taken in visible light with the spacecraft’s wide-angle camera on October 28, 2015. The view was acquired at a distance of approximately 77 miles (124 km) from Enceladus. Scale bar – 1 km. Image credit: NASA / JPL-Caltech / Space Science Institute.
After the October 28 flyby, only one close Enceladus flyby remains before the end of the Cassini mission in 2017.
The encounter is planned for December 19, 2015, when Cassini will measure the amount of heat coming from the moon’s interior. The flyby will be at an altitude of 3,106 miles (4,999 km).
