Cassini flies over Dione around 2:30 p.m. today, zipping just 295 miles over the surface of it. Gravitational measurements will hint at whatever might be going on under the icy crust of the moon.
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Since 2004, NASA’s Cassini spacecraft has been orbiting Saturn and its moons. Mission controllers expect fresh images to begin arriving on Earth within a couple of days following the encounter.
Also, scientists will be gaining high-resolution spectrometry data of its surface and infrared instruments will map out regions on the 700 mile-wide moon that are known to have “unusual thermal anomalies”, according to a NASA news release. This flyby will be the fifth targeted encounter with Dione during Cassini’s tour of Saturn.
The bright network of fractures on Dione (698 miles or 1123 kilometres across) was seen originally at poor resolution in Voyager images and was labeled as “wispy terrain”.
Bonnie Buratti is a Cassini science team member at NASA’s Jet Propulsion Laboratory in Pasadena, California.
The picture, obtained from a distance of about 68,000 miles (approximately 110,000 kilometers) reveals a network of chasms crisscrossing the orb’s surface. Now mission scientists are excited for the mission’s fifth pass, as it’s their last opportunity to unravel Dione’s mysteries. Instead, over the last few billion years, they were probably captured when straying too close to the planet. However we have by no means discovered the smoking gun.
The probe, launched in 1997, passed by Jupiter before settling into orbit around Saturn in 2004.
After more flybys of Saturn’s moons scheduled for late 2015, Cassini will move into position for investigating the space between Saturn and its rings. It’s final year will be marked by repeatedly diving between the gas giant and its breathtaking rings before crashing into Saturn’s atmosphere in 2017.
“This will be our last chance to see Dione up close for many years to come”, said Scott Edgington, Cassini mission deputy project scientist at JPL.
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Back home, scientists are hoping that data and images obtained this time in combination with earlier flybys will provide answers to the question whether any ongoing geologic activity is present on the moon similar to its sister moon the geyser spotting Enceladus.
