PORTLAND, Ore. NASA's Cassini spacecraft orbiting Saturn made its closest fly-by of the moon Enceladus on Thursday (Oct. 9). Analyzing molecules being ejected from geysers on the moon's surface, Cassini will provide scientists with data on whether water is present on the satellite.
"We expect that the core is liquid water. Water is the essence of all kinds of life, so there can be some interesting organic molecules," said Tamas Gombosi, chair of the University of Michigan Department of Atmospheric, Oceanic and Space Sciences. "But it would be too far to go and say that we are looking for life." Gombosi coordinates studies that analyze data from the multiple plasma instruments on Cassini.
This week's fly-by was the closest yet of any of Saturn's moons, whizzing just 16 miles above the surface. It will take several weeks to analyze the data, the results of which will be available by mid-November.
|Enceladus was imaged by Cassini, the NASA spacecraft during its closest fly-by of the Saturn moon on Thursday (Oct. 9). Cassini analyzed molecules being ejected from geysers on the surface of Enceladus.|
If the mission can verify that liquid water, perhaps even an ocean, exists beneath the surface of Enceladus, then analysis of the organic molecules spewed from its geysers could indicate if the prerequisites for life exist there. Organic molecules have already been detected by remote instrumentation.
Cassini flew directly through a plume of molecules being ejected by geysers on Enceladus, allowing its instruments to directly analyze its particles and gases--hopefully identifying individual molecules in the moon's environment, including ions and isotopes spewed from deep in its interior. Data would provide a glimpse into the moons past and continuing evolution.
The geysers were discovered by Cassini three years ago, raising the possibility of analyzing the moon for habitability. Enceladus is Saturn's sixth-largest moon, approximately 313 miles in diameter (about the distance across Arizona), and orbits within the planet's outer-most ring.
A second fly-by later this month (Oct. 31) will approach as close as 122 miles from Enceladus's surface, and will focus on photographing "tiger stripe" fractures on its surface that appear to be changing--indicating that the moon is not dead, but still evolving.
Two more fly-bys are also scheduled in November and early December, along with another pair over the next two years.
The Cassini Equinox Mission put the spacecraft in orbit around Saturn in 2004. It previously deployed a lander, called Huygens, which is now on the surface of Saturn's moon Titan.
The Jet Propulsion Laboratory (Pasadena, Calif.) designed Cassini and manages the mission for NASA. Cassini is acooperative effort of NASA, the European Space Agency and the Italian Space Agency.