NASA’s Cassini spacecraft is in the final leg of its mission during which it will conduct daring flybys – closest it has ever been to the planet’s rings to unravel secrets that haven’t been known till date.
Saturn’s rings still pack within them quite a lot of mystery and while the Cassini spacecraft has provided us with a tonne of information already, there is still much more to learn. Mission scientists at NASA have said that as a part of the grande finale of the mission, the spacecraft will fly the closest it has ever been near Saturn’s rings.
The “ring-grazing” orbits of Cassini will begin on November 30, 2016 and for this the spacecraft will be aided by gravitational nudge from Saturn’s moon Titan. The reason mission team is calling this Cassini’s Ring-Grazing Orbits as the spacecraft will be skimming past the outer edge of the rings and during these maneuvers and during this will sample particles and gases that it crosses while in the ringplane using two onboard instruments.
As par the plan, the ring-grazing orbits from November 30 and April 22 will see the spacecraft circle high over and under the poles of Saturn diving every seven days through the unexplored region at the outer edge of the main rings. Cassini will be carrying out a total of 20 such dives according to NASA. On many of these passes, Cassini’s instruments will attempt to directly sample ring particles and molecules of faint gases that are found close to the rings.
NASA revealed that during the first two orbits, Cassini will pass directly through an extremely faint ring produced by tiny meteors striking the two small moons Janus and Epimetheus. Subsequently in March and April, the spacecraft will pass through dusty outer reaches of the F ring – a ring that marks the outer boundary of the main ring system. Saturn has several other, much fainter rings that lie farther from the planet.
During these orbits, Cassini will pass as close as about 90,000 kilometres 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 and that’s when the mission will effectively come to a close after nearly 20 years of operation in space, since the spacecraft is running low on fuel. During its grand finale, Cassini will pass as close as 1,628 kilometres above the clouds as it dives repeatedly through the narrow gap between Saturn and its rings, before making its mission-ending plunge into the planet’s atmosphere on September 15, 2017. Check out the video below: