Astronomers have long known that one of Saturn's innermost moons, Pan, has an odd shape. On March 9, NASA shared stunning close-ups of the icy moon captured by the Cassini spacecraft.

Cassini Images Reveal Ravioli Shape Of Saturn's Moon Pan

The U.S. space agency likened the shape of the moon to a ravioli, a dumpling made of two layers of pasta dough. The images were taken when Cassini flew by Pan on March 7 as the spacecraft made a close approach at a proximity of just 15,268 miles from the tiny moon.

The pictures are expected to reveal the geology and shape of the natural satellite, but they are also set to be among the last data that the Cassini spacecraft would send back to Earth, as 2017 will be the last year of the probe's epic scientific voyage.

The Grand Finale

After more than 12 years of studying the rings and moons of Saturn, the Cassini spacecraft is already on its final year. The mission will conclude in September 2017 with a final plunge in the atmosphere of the ringed planet.

During this final phase called the Grand Finale, the probe will dive into Saturn's atmosphere and transmit data about the chemical composition of the planet until it loses its signal. The probe's friction with the atmosphere is expected to burn it like a meteor soon afterward.

The final phase is set to start in April with a close flyby of the Saturn moon Titan, which will alter the spacecraft's orbit so that it will pass through the gap between the planet and its rings, a yet unexplored space measuring just about 1,500 miles wide.

"We've used Titan's gravity throughout the mission to sling Cassini around the Saturn system," said Cassini project manager Earl Maize from NASA's Jet Propulsion Laboratory. "Now Titan is coming through for us once again, providing a way for Cassini to get into these completely unexplored regions so close to the planet."

Scientists expect the spacecraft to make 22 plunges through this gap with the first dive expected to happen on April 27. Researchers anticipate gathering valuable scientific data during the Grand Finale, during which the probe will make the closest observation of the planet, map its magnetic and gravity fields, and gather ultra-close views of the atmosphere.

Settling Questions About Age Of Saturn's Rings

With data from the final phase of the mission, researchers hope to gain insights into the interior structure of the ringed planet, the accurate length of one Saturn day, and the total mass of the planet's rings, which could help settle questions about their age.

"I am especially interested in Cassini's measurement of the mass of Saturn's rings," Larry Esposito, of the Laboratory for Atmospheric and Space Physics in Boulder, Colorado said. The mass of the rings will help scientists determine if the rings were recently created, or if they are as old as the solar system, which could offer insights into how planets form.

"It will be a major scientific discovery either way, with implications for the formation of planets in proto-planetary discs."