Cassini to Investigate Saturn's 'Death Star'

Image comment: A photo of Mimas collected by Cassini in 2005
Image credits: NASA / JPL / Space Science Institute

For fans of the Star Wars series, the Death Star is one of the most renowned symbols, right next to the light saber. But very few people know that the destroyer has an actual counterpart, the Saturnine moon Mimas. The celestial object is rather small, but it also features a structure on its surface called the “Eye,” which resembles the Imperial spacecraft's weapon. At this point, the NASA/ESA orbiter Cassini is getting ready to take the closest look ever at this feature, experts at the American space agency's Jet Propulsion Laboratory (JPL), in Pasadena, California, write on their official website.

The Saturnine moon has had a long and rough history, in the sense that it has been battered by space impacts with meteorites and asteroids for a long time. This is evident all over its surface, but especially in the Eye, which is actually the mark left behind by a powerful impact. Cassini imaged the body before, in 2005, when it passed 228,000 kilometers (142,500 miles) away from it. But during the new flyby, which will take place tomorrow, February 13, the spacecraft will fly a lot closer, and JPL experts managing it hope to capture high-resolution images of its surface.

“Mimas bears the mark of a violent, giant impact from the past – the 140-kilometer-wide (88-mile-wide) Herschel Crater – and scientists hope the encounter will help them explain why the moon was not blown to smithereens when the impact happened. They will also be trying to count smaller dings inside the basin of Herschel Crater so they can better estimate its age,” the scientists write. If a crater on another planet or moon features many smaller impact craters within, then this means it is very, very old. Conversely, if it features very few, and if its edges are still clearly visible and not eroded, then it was produced relatively recently, just millions of years ago.

According to plans, Cassini will fly as close as 9,500 kilometers (5,900 miles) above the surface of Mimas. It will use its suite of scientific instruments to catch unique views of the surface, but also to analyze the moon's thermal signature, as well as the composition of its rocks. The Herschel Crater is enormous on its surface, covering almost one third of the area. The moon itself is only 396 kilometers (246 miles) in diameter. “The walls of the crater are about 5 kilometers (3 miles) high, and parts of the floor are approximately 10 kilometers (6 miles) deep,” the JPL team adds.