On November 30, NASA’s Cassini spacecraft will begin the first of its many ring-grazing orbits around Saturn as it closes in on its grand finale.
The spacecraft will perform of total of 20 ring-grazing orbits until April 22 diving every seven days through the unexplored region at the outer edge of the main rings offering unprecedented opportunities to observe the menagerie of small moons that orbit in or near the edges of the rings, including best-ever looks at the moons Pandora, Atlas, Pan and Daphnis.
NASA says that through these orbits, the spacecraft will provide some of the closest-ever studies of the outer portions of Saturn’s main rings (the A, B and F rings). Some of Cassini’s views will have a level of detail not seen since the spacecraft glided just above them during its arrival in 2004.
As per the plan, the spacecraft will begin imaging the rings in December along their entire width, resolving details smaller than 0.6 mile (1 kilometer) per pixel and building up Cassini’s highest-quality complete scan of the rings’ intricate structure.
Throughout these 20 orbits, the mission will continue investigating small-scale features in the A ring called “propellers,” which reveal the presence of unseen moonlets. Because of their airplane propeller-like shapes, scientists have given some of the more persistent features informal names inspired by famous aviators, including “Earhart.” Observing propellers at high resolution will likely reveal new details about their origin and structure.
And in March, while coasting through Saturn’s shadow, Cassini will observe the rings backlit by the sun, in the hope of catching clouds of dust ejected by meteor impacts.
During these orbits, Cassini will pass as close as about 56,000 miles (90,000 kilometers) above Saturn’s cloud tops. But even with all their exciting science, these orbits are merely a prelude to the planet-grazing passes that lie ahead. In April 2017, the spacecraft will begin its Grand Finale phase.