15 September, 2017
It was the first mission that was launched to specifically study Saturn and was the first to go near enough to the planet to take detailed images since the Pioneer and Voyager crafts flew by it, several decades before it.
However, NASA TV is broadcasting live online video of the final stages of Cassini's "Grand Finale", the moment its last stream of data comes in, and - by extension - confirmation that it's died. So when NASA finally put the thing in a death spiral around Saturn in April, you'd think that the mission's scientists would have breathed a sigh of relief. There are fascinating images of geysers shooting from Enceladus's south pole, handsome images of Saturn's rings (including one with Saturn's shadow falling on them), and a zoomed-in view of Epimetheus (another of Saturn's moons). The signal shall be lost at around 930 miles (1,500 Kilometeres) above Saturn's cloud tops.
To study Saturn and its moons from close up and in the process learn more about the solar system and how it was formed.
Because Saturn is so far away, Cassini's last-gasp signals will be received on Earth 83 minutes after the probe's destruction.
"The spacecraft's final signal will be like an echo. It will radiate across the solar system for almost an hour and a half after Cassini itself has gone", Cassini project manager at Nasa's Jet Propulsion Laboratory in Pasadena, California, Earl Maize said.
"We just didn't have the understanding of how important it was to bring the public along with what we are doing", said Jim Green, NASA's planetary science director at the space agency's headquarters in Washington, D.C. "Cassini has done some pretty spectacular stuff - but not many people know about it". It will then make a final dump of its entire memory in a download to mission control before reconfiguring itself to send all its science data and telemetry live. This way, Cassini will be able to measure gravity and magnetic fields, evaluate the total main-ring mass to estimate the system's age and longevity, and sample Saturn's ring particles, innermost radiation belts and upper atmosphere before burning up. Cassini has collected 450,000 images using a visible light camera. The "Wave at Saturn" campaign was the first to provide earthlings with advance notice that their picture was being taken from an interplanetary distance. Image credit: NASA / JPL-Caltech / Space Science Institute.More news: Angelina Jolie wishes kin to be a part of showbiz
When was Cassini launched and how long did it take to reach Saturn? Some vertical relief is apparent in this view, with higher clouds casting shadows over those at lower altitude.
Although Cassini will soon cease to exist, at least one full-size representation of the venerable spacecraft will remain on display.
Intrigued by Cassini's discoveries, scientists have submitted concepts for future "spacecraft to drift on the methane seas of Titan and fly through the Enceladus plume to collect and analyze samples for signs of biology" that are now under consideration, according to NASA.
Today (Sept. 14) at 3:58 p.m. EDT (1958 GMT; 12:58 p.m. PDT), Cassini will snap its final photo, targeting the patch of atmosphere where it will meet its fiery fate.
The scientists wanted to get their money's worth from the £2.9 billion mission and so packed Cassini with instruments, leading to comparisons with a multi-purpose Swiss army knife.