Hyperion, a moon of Saturn, will be visited by the Cassini spacecraft On May 31. This flyby will be the last made by the spacecraft orbiting the planet. Every time the spacecraft has flown past Hyperion, it went along the same side of the satellite — so mission planners are hoping to see the other side of the moon on this trip.
The Cassini spacecraft made its closest approach to the sponge-like moon on September 26, 2005. During this run, the spacecraft will reach its closest point to the moon – around 21,000 miles away – at 9:36 a.m. EDT on the last day of May.
"Cassini's next notable flyby after May 31 is slated for June 16, when the spacecraft will pass 321 miles (516 kilometers) above icy Dione. That flyby will represent the mission's penultimate close approach to that moon. In October, Cassini will make two close flybys of the active moon Enceladus, with its jets of icy spray, coming as close as 30 miles (48 kilometers) in the final pass," read a post on the NASA website.
Late in 2015, Cassini will race away from the equatorial plane of the planet, where satellites travel. This will move the spacecraft into position for high-risk maneuvers planned for the final year of the mission.
Hyperion, which has a diameter of around 168 miles, tumbles in a near-random fashion, making it almost impossible to predict which side will be facing the cameras when Cassini flies past. Its body has a surprisingly low density, and astronomers believe impacts with asteroids have compressed the surface, producing its sponge-like appearance.
Cassini was launched from Earth on October 15, 1997, entering orbit around Saturn on July 1, 2004. The vehicle was paired with the Huygens lander — which touched down on the surface of the giant moon Titan, becoming the first vehicle in history to land on the Saturnian satellite. Cassini was named in honor of the astronomer Giovanni Cassini, who discovered the largest gap in the ring system surrounding Saturn.
Just as human beings have senses that can record information from a distance – notably seeing and hearing – Cassini is also equipped with remote and direct sensing equipment.
"However, the instruments on the Cassini spacecraft are much more advanced than our own. Cassini can 'see' in wavelengths of light and energy that the human eye cannot. The instruments on the spacecraft can 'feel' things about magnetic fields and tiny dust particles that no human hand could detect," NASA officials report.
In the last phase of its mission, Cassini will undertake several daring dives between the innermost ring of Saturn and the planet itself, in an effort to understand the system like never before.
