London, March 15: NASA's Cassini spacecraft, which made an unprecedented flyby of Saturn's moon Enceladus on March 12, has failed in an experiment that scientists had hoped would help reveal the origin of the plumes on the moon. Enceladus has huge geysers erupting from giant fractures on its south pole, who throw them out to a distance of three times the radius of the moon.
The source of the geysers is of great interest to scientists who think liquid water, perhaps even an ocean, may exist in the area. The Cassini spacecraft has survived its passage though the ice plume of Enceladus and sent back close-up images and other data from this mysterious moon of Saturn, but not everything went according to plan.
According to a report in New Scientist, as Cassini flew over the small moon on 12 March, passing only 200 kilometres from the base of the plume, an "unexplained software hiccup" prevented the spacecraft's Cosmic Dust Analyzer (CDA) from transmitting data to the onboard computer.
New software, designed to improve the ability of CDA to count particle hits, may be to blame. "We don't know why it did not work," said the instrument's principal investigator, Ralf Srama of the Max Planck Institute of Nuclear Physics in Heidelberg, Germany.
Among other things, CDA would have been looking for mineral grains, which might act as nucleation points for the ice crystals and could reveal whether the rocky core of Enceladus is connected with whatever drives the geysers.
Other instruments on board were working fine. However Cassini will return in August, perhaps passing even closer to the source of the plumes, and again in October, when the dust analyser should get another chance to see exactly what is coming out of Enceladus.