NASA Saturn Probe passed away 1 year ago today

NASA's Cassini Saturn probe may have disappeared, but it is far from forgotten.

A year ago, Cassini intentionally plunged into the thick atmosphere of the ringed planet (September 15), ending a long spell of 13 years through the Saturn system.

Cassini's observations have already revolutionized the scientists' understanding of the gaseous giant, its iconic rings and its many moons. And more revelations will come. [Cassini’s Greatest Hits: The  Best Images of Saturn]

"In a lot of ways, with this massive 13-year-old data stream, we really only skimmed over cream," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena. California, told Space.com. "But there is more in the data."

Some of the innovations analyzed will be published early next month. A series of articles based on observations made by Cassini in his final audacious Saturn orbits will be published on October 5 in the prestigious journal Science, Spilker said.

NASA is funding an additional year of data analysis for the mission, she added. But the study of Cassini's observations and discoveries arising from these works will not dry up when funding from the agency will do so.

"For decades to come – probably until we return to the Saturn system with a Cassini-like mission – I think scientists will review this data," Spilker said.

A long and rich mission

The Cassini-Huygens mission of $ 3.9 billion, a joint operation of NASA, the European Space Agency and the Italian Space Agency, was launched in October 1997 and came into orbit around Saturn in the night of June 30, 2004.

On Christmas day 2004, a lander named Huygens was separated from the Cassini mothership. Three weeks later, Huygens lands on Titan, the huge moon of Saturn, causing the first soft landing of the outer solar system.

Huygens stopped transmitting data at home about 90 minutes after landing, but the Cassini orbiter has continued to zoom into the Saturn system for years and years. The spacecraft collected a wealth of data on the planet, its rings and moons, some of which were downright astonishing.

For example, in 2005, Cassini spotted geysers in the southern polar region of the frozen satellite Enceladus. The probe found that the geyser material contains water and organic chemicals – the constituent elements of carbon that we know – and that this material comes from an immense ocean of salty liquid water that flows under the ice of the 313-mile-wide (504-kilometer) moon. [Photos: Enceladus, Saturn’s Cold, Bright Moon]

Scientists at the mission determined that Enceladus's ocean also contained sources of chemical energy that could support life. (Another fun fact about geysers: the plume of material that they emit generates the Saturn E ring.)

And the Cassini mission has lifted the veil over Titan, with a width of 5200 km (5,150 km), which is obscured by a thick and foggy atmosphere. Cassini's radar observations made it possible to observe river systems, lakes and seas, not in the water, but in liquid hydrocarbons.

The air of the big moon is full of potential chemical energy, so it is possible that these lakes and seas support life – organisms that should be very different from those found here on Earth and which require liquid water. (That's not to say that water-based life could not exist anywhere on Titan, the moon also seems to have an ocean of sub-surface water.)

Indeed, the life potential of Enceladus and Titan helped to determine the fate of Cassini. The members of the mission team wanted to make sure that the spaceship, which was running out of fuel in the summer of 2017, never contaminated one of the two moons. with microbes from the Earth. The decision was therefore made to send the mission in a burst of glory, high in the clouds of Saturn.

Sustainable legacy

Cassini will probably be remembered for identifying Enceladus as an oceanic world that could save her life and for bringing to light the fascinating Titan, Spilker said. But public awareness is another big part of the mission's legacy. [In Photos: Cassini’s Last Views of Saturn]

Cassini's gorgeous photos – Saturn's clouds, rings of the planet, Enceladus, Titan's jets, strange ravioli and moon – and countless other objects and features – have transported millions of people to Earth. These images are always inspiring today, in fact; NASA continues to publish and showcase Cassini's photos, even though the spaceship itself is only a swirl of ashes in the air of Saturn.

The mission team has always given priority to public awareness. For example, NASA officials and Cassini scientists organized a campaign in July 2013 called "Wave at Saturn", asking landlords to say hello to Cassini during a solar eclipse of the Saturn system. the gas giant has erased the sun from the spacecraft's point of view.

And last week, JPL won an Emmy Award for its efforts to promote Cassini's "Grand Finale" campaign to the masses.

Much of Cassini's legacy however remains to be written. As Spilker said, other discoveries are waiting to be made, hidden in the mission's data sets. And then, there are the potential missions of Saturn to come – missions inspired and motivated by 13 years of Cassini's observations, which revealed the complexity, diversity and intrigue of the Saturn system.

"Oh, we must go back," said Spilker.

There is no Saturn mission in NASA's books yet, but that could change quickly. An effort called Dragonfly, which would send a robotic quadricopter to explore Titan's sky, is one of two finalists NASA is considering for the next launch of its New Frontiers program. (New Frontiers' missions are medium-cost projects capped at $ 1 billion, examples include the New Horizons Pluto probe and the Juno Jupiter orbiter.)

The other finalist is a comet return mission called CAESAR (Comet Exploration Samples Return Mission). NASA is expected to announce its selection next summer; the mission will probably be launched in the mid-2020s.

Follow Mike Wall on Twitter @ michaeldwall and Google+. follow us @ Spacedotcom, Facebook or Google+. Originally published on Space.com.