NASA's Cassini spacecraft is beginning a series of "ring grazing" orbits today to study Saturn's rings and moons before it makes a death plunge into the planet's atmosphere next year.
Cassini is using the gravitational pull from Saturn's largest moon, Titan, to begin the tilted orbits. Between today and April 22, Cassini will circle over and under the poles of Saturn once every seven days, for a total of 20 times. Engineers have been pumping up Cassini's orbit around Saturn this year to increase its tilt for the mission.
NASA scientists are calling this phase of the mission Cassini's ring-grazing orbits because the spacecraft will be skimming past the outer edge of the rings, where instruments will collect particles and gases as it crosses the ring plane, said Linda Spilker, the Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.
Cassini's ring-grazing orbits will offer "unprecedented opportunities" to observe the small moons that orbit the planet near the edges of Saturn's rings, including Pandora, Atlas, Pan and Daphnis. The region on the outer edge of Saturn's main rings has been unexplored until now.
Cassini was launched in 1997 and has been touring Saturn's system since it arrived there in 2004 to study the planet and its rings and moons, producing ground-breaking research and stunning images of our solar system's second-largest planet.
During the orbits, Cassini will pass as close as about 56,000 miles above Saturn's cloud tops. In April the spacecraft will begin its grand finale phase, in which it will pass as close as 1,012 miles above the clouds before it dives through the narrow gap between Saturn and its rings and into the planet's atmosphere. After nearly 20 years in space, Cassini is low on fuel, so the mission is drawing to an end.
NASA called Cassini's suicidal plunge the mission's "dramatic endgame."
The spacecraft has made several discoveries in the Saturnian system during its journey, including seas of liquid methane on Titan and a global liquid water ocean beneath the frozen surface of Enceladus, Saturn's sixth-largest moon.