Earlier this week , NASA ’s Saturn probe , Cassini , zip past the heavily cratered , icy moonDionefor onefinal close flyby .
So far , 62 moons have been discovered orbit around Saturn , though only 53 have officially been key . chance on in 1684 , Dione is a small lunar month 1,123 kilometers ( 698 mi ) in diam , and it orbits Saturn every 2.7 Clarence Shepard Day Jr. at a distance of 377,400 kilometers ( 234,000 miles ) – about the same aloofness that our Sun Myung Moon orbits around Earth .
“ Dione has been an secret , giving hints of participating geological process , include a ephemeral atmosphere and grounds of trash volcanoes , ” Bonnie Buratti of NASA ’s Jet Propulsion Laboratory aver in astatementlast calendar week . “ But we ’ve never find the smoking gun . The 5th flyby of Dione will be our last chance . ” Dione is n’t as active as the geyser - spouting Enceladus , though we have seen that its fractured open is shroud bybright linear chasmsthat contrast dramatically with its more distinctive rotund shock craters ( pictured above ) .
This flyby ’s close access – within 474 kilometer ( 295 mile ) of Dione ’s surface – occurred at 2:33 p.m. Eastern Time on Monday , August 17 . This was the fifth targeted encounter with Dione , and so as to fine - tune its trajectory , Cassini had executed a 12 - second burn using its pusher on August 9 . A mint of coming analysis are planned for Dione . Cassini ’s cameras and mass spectrometer have taken a in high spirits - resolve looking at at the moon ’s north pole , which has n’t been observed closely . Gravity - science data will disgorge light on the moon ’s home structure and the rigidity of the out shield . And a smorgasbord of other instruments are mapping areas that immobilize heat and searching for rubble particles that are let out . Someraw imageshave already been have , and you’re able to graze themhere .
A persuasion of Saturn ’s moon Dione appropriate by NASA ’s Cassini ballistic capsule during aclose flyby on June 16 , 2015 . The diagonal line near the upper left hand is the rings of Saturn in the distance . NASA / JPL - Caltech / Space Science Institute .
Cassini ’s closest - ever flyby of Dione submit place during December 2011 at a distance of 100 kilometers ( 60 miles ) . That and other previous close flybys have yielded sharp aspect of Dione ’s terrain , which was first honour during the Voyager foreign mission . The tenuous wispy crease trance in ( poor resolution ) Voyager images from ten ago turned out to be a system of plait canyons with bright paries .
This flyby is our last chance to see Dione up close for many long time . Cassini has been orbiting Saturn since 2004 , and after a serial publication of close-fitting Sun Myung Moon flybys scheduled for the residual of this twelvemonth , the ballistic capsule will allow Saturn ’s equatorial plane to get going correct up for the mission ’s concluding year : In 2017 , Cassini will repeatedly dive through the blank between Saturn and its annulus .
Next up on theSaturn Tour , a Titan flyby is scheduled for September 28 .
