NASA prepares for an “in your face” encounter between its Cassini spacecraft and Saturn’s moon Enceladus, the closes one to date, the agency's official site reports. The approach will take Cassini along the edges of the erupting geysers at Enceladus’ South Pole, giving it the opportunity to gather samples of water-ice, dust and gas in the plume, which are later to be studied.

Researchers have been most interested in the source of the geysers, in the hope that they might find a source of water in the area. “This daring flyby requires exquisite technical finesse, but it has the potential to revolutionize our knowledge of the geysers of Enceladus,” said Alan Stern, associate administrator of NASA’s Science Mission Directorate, Washington.

Cassini will be at approximately 200 kilometers (120 miles) above Enceladus’ surface when flying by the edge of the plumes, and 50 kilometers (30 miles) above the surface at its closest approach. NASA scientists have established that the distances will not endanger Cassini, not even when above the geysers, as the particles in the plume are small enough so as not to pose any threat.

“There are two types of particles coming from Enceladus, one pure water-ice, the other water-ice mixed with other stuff,” said Sascha Kempf, deputy principal investigator for Cassini’s Cosmic Dust Analyzer at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. “We think the clean water-ice particles are being bounced off the surface and the dirty water-ice particles are coming from inside the moon.”

For the time being, all these remain assumptions, but the flyby is intended to do just that, offer more information in support or against the theory. Scientists are trying to uncover whether there are differences between the composition of the gases in the plume and that of the material that surrounds Saturn’s moon.

Cassini will be at its fourth flyby of Enceladus this year, and this year will also complete its first mission, a four-year tour of Saturn, NASA reports. Depending on the outcome of this flyby, Cassini will execute several more, even closer than this one. NASA collaborated with the European Space Agency and the Italian Space Agency for the Cassini project.

Image credits: NASA