As the Cassini orbiter is entering the final phase of it’s mission around Saturn, it will get a final look at Saturn’s moon Hyperion.
This moon, which is only 270 kilometers wide, has a trademark spongy appearance. In previous flybys of Hyperion, only one side has ever been seen so the Cassini team will try to catch a glimpse of the other side. Pictures of Hyperion’s one side show it is heavily cratered and this is what gives it its spongy appearance. Cassini scientists are hoping to see the far said of Hyperion to get a better idea of its composition. Seeing the other side is no easy task however. Because of Hyperion’s irregular shape, it tumbles around as it orbits Saturn making it very difficult to predict what side will be visible to Cassini at the time of the flyby. The flyby will occur on May 31 at approximately 6:30 am at a distance of 34,000 kilometers.
Entering the final stage of its mission, Cassini will also get more looks at some of Saturn’s other moons, including Enceladus and the trademark Rings of Saturn.
Cassini will fly by Dione at a distance of 516 kilometers on June 16 and will then proceed to Enceladus. Enceladus is Saturn’s most interesting moon because of its prospects for life. It is thought to have a pocket of liquid water below its surface in the South Pole that could be inhabited by alien microbes. Cassini will flyby Enceladus at a distance of just 48 kilometers! This will be an incredibly close flyby. For reference, the International Space Station orbits the Earth at a distance 250 kilometers.
In 2016, Cassini will finish its mission by exploring Saturn’s Rings in what the Cassini team is calling the ‘Grand Finale’. It will pass between Saturn and it’s innermost ring a total of 22 times starting later this year and ending in September 2017. During this time, Cassini will map out Saturn’s magnetic field and gravity as well as determine the amount of matter in Saturn’s rings. At the end of the mission, Cassini will be intentionally crashed into Saturn to avoid possible contamination of its moons.
Cassini was launched in 1997 and arrived at Saturn in 2004. In its 11 years orbiting Saturn and it’s moons, it has made several discoveries. These include the discovery of water plumes in the south pole of Enceladus, hydrocarbon lakes on Titan and the dynamics of Saturn’s rings. 2017 will mark the end of a truly epic mission from Cassini.