NASA’s Cassini spacecraft will today perform a flyby of Saturn’s moon Enceladus, hoping to swoop through one of the many plumes of liquid coming from what is believed to be a subsurface ocean.
The flyby through plumes at the moon’s south pole will take place today at 1 p.m. EDT (5 p.m. GMT), but the first scientific results are not expected for days or even weeks. If successful, this will be the deepest ever dive through a plume of Enceladus.
During the flyby, the spacecraft will come within just 50 kilometers (30 miles) of the surface, hoping to sample some of the components from one of the plumes. The spacecraft has done so before, with a study released yesterday suggesting they may contain evidence that the moon’s interior is similar to that of a primitive meteorite.
It is possible, too, that the ocean could be habitable for microbial organisms, which could use hydrogen as an energy source. This flyby could provide invaluable new data on the composition of the subsurface ocean on Enceladus, and hint at its habitability.
"Enceladus is not just an ocean world – it's a world that might provide a habitable environment for life as we know it," Cassini program scientist Curt Niebur said in a media briefing on Monday.
Check out the video above for more information on the flyby. ScienceAtNASA.
The ocean is thought to be heated by tidal forces from Saturn and another of its moons, Dione. Water is then expelled from vents at a temperature of at least 90°C (190°F), and ejected out from canyons on the surface known as tiger stripes.
While it is not capable of actually detecting life, data from the spacecraft’s instruments could reveal new information about hydrothermal activity taking place at the bed of the ocean, which may be a source of hydrogen. We already know that life on Earth can exist around hydrothermal vents. Could the same be true of Enceladus?
The flyby may also reveal whether the plumes are shaped like columns, or curtain-like icy eruptions – or both. The quantity of the icy material will also be measured.
This is the closest Cassini will come before the mission ends in 2017, having been in orbit since 2004, concluding with a dive into Saturn’s atmosphere when the spacecraft runs out of fuel. Another flyby in December will bring it within 5,000 kilometers (3,000 miles) of the surface, but no other flyby is planned below 22,000 kilometers (14,000 miles).
Therefore, until another mission is sent to Saturn – of which there is nothing in development – this will be our last up-close examination of the plumes, which may hold vital clues as to what other life, if any, exists in the Solar System.