Grand Finale part 2: Cassini completes second epic dive into Saturn’s rings

Illustration of Cassini crossing the ring plane between Saturn and its innermost rings .Cassini has now completed its second dive into the rings of Saturn, with 20 left to go during the Grand Finale. Image Credit: NASA/JPL-Caltech

Cassini’s “dance” with Saturn’s rings continues – the probe has now completed its second dive into the rings (orbit 272), specifically the gap between the innermost rings and Saturn itself. That leaves 20 more similar dives to go, as part of the Grand Finale phase of Cassini’s mission before the fateful end on Sept. 15. This is the closest that any spacecraft has ever come to Saturn, showing the rings and the planet itself in detail never seen before.

This dive is a little different from the first one. For the first time, Cassini “rolled” to calibrate its magnetometer (MAG) for the high-intensity magnetic field observations to be performed when the spacecraft is nearest Saturn. Other highlights of this dive included:

  • Cassini’s imaging cameras, the Imaging Science Subsystem (ISS), took advantage of the last opportunity to observe Saturn’s rings at extremely high phase angles while the Sun is hidden behind Saturn, allowing the instrument to survey faint ringlets in the main rings, many of which are difficult to observe outside of this geometry. The ISS also collected images to produce a movie to monitor various structures in Saturn’s D ring.
  • The spacecraft’s Composite Infrared Spectrometer (CIRS) observed Saturn’s moon Rhea in infrared to narrow down the composition and structure of the moon’s surface material.
  • During this orbit, Cassini was within 2,930 kilometres (1,820 miles) of Saturn’s 1-bar level. Cassini also passed within 4,780 kilometres (2,980 miles) of the inner edge of Saturn’s D ring.

Read the rest of my article on AmericaSpace.

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