A NASA spacecraft has detected oxygen around one of Saturn's icy moons, Dione, the BBC reported. The discovery supports a theory that suggests all of the moons near Saturn and Jupiter might have oxygen around them. The study has been published in Geophysical Research Letters. The discovery was made using the Cassini spacecraft, which flew by Dione nearly two years ago. Instruments on board the unmanned probe detected a thin layer of oxygen around the moon. It suggests there is a process at work around the solar system's gas giants, Saturn and Jupiter, in which oxygen is released from their icy satellites.