Added by Erik West on October 29, 2015
NASA reported on Thursday that the Cassini spacecraft is healthy after it completed its historic flyby of Saturn’s moon Enceladus.
Cassini made the flyby in an attempt to analyze the chemistry of plumes of water from Enceladus’ south pole. The water is emanating from the region in huge plumes, or possibly huge jets, stretching thousands of kilometers into space.
Scientists say Enceladus, Saturn’s sixth-largest moon, covered in a layer of ice that’s about 25 km thick is, host to a global ocean kept from freezing by a phenomenon called tidal heating. Tidal heating is caused by the pull of gravity from Saturn and another moon close to Enceladus causing the interior of Enceladus to flex and generate heat — enough to keep the water in liquid form.
NASA reports that the water under the thick ice may be able to support microbial forms of life, similar to those deep under our own oceans. So far, Enceladus is considered to be the most promising body within our solar system to be able to support life.
In a media briefing Cassini program scientist Curt Niebur said, “Enceladus is not just an ocean world – it’s a world that might provide a habitable environment for life as we know it.”
Cassini passed to within 50 km of the source of the plumes of water emanating from the moon. Among the mission’s objectives are to determine the chemical makeup of the water — specifically to detect molecular hydrogen, an indicator that vent systems similar to those found in our oceans exist. Those vent systems are known to support life here on earth.
“The amount of hydrogen emission will reveal for us how much hydrothermal activity is actually occurring on that seafloor – with implications for the amount of energy available,” said Cassini project scientist Linda Spilker.
While the flyby occoured at 4 p.m. GMT on Tuesday, scientists say it may take until the end of the week to see initial photos from the historic flyby. Data about the gasses and particles Cassini detected is expected over the following weeks.
Dr. Spilker added that in the weeks that follow, “…we’ll do a more detailed analysis, to really help us understand what’s going on in that tantalizing ocean on Enceladus.”
This visit to Enceladus is the closest Cassini will come to the moon’s surface. It’s next flyby is expected to be within 5,000km of the surface, followed by another 22,000km above the icy surface.
In 2016, Cassini is scheduled to put itself into orbit among Saturn’s rings to study them up close. Then in 2017, at the end of Cassini’s mission, it will be commanded to plunge into Saturn’s atmosphere where it will be destroyed.
Cassini completed a close flyby of Saturn’s sixth largest moon, Enceladus on Tuesday. The space probe is studying huge plumes of water emanating from jets at the moon’s south pole. The jets are water from the moon’s global ocean, thought to possibly be able to support simple forms of life. Photo: rendering of Cassini’s flyby/NASA-JPL