Neutral Composition of Enceladus' Plume

In July of 2005, the Cassini spacecraft passed within 170 km of the Saturnian moon Enceladus, discovering a substantial plume of icy material emanating from the south pole. Preliminary conclusions on the composition were performed on data obtained by the Ion and Neutral Mass Spectrometer (INMS) showing clear signs of H2O, CH4, H2, CO2, an unidentified peak at mass 28 (N2 or CO) and trace quantities of simple organics. Recent Cassini flybys through the Enceladus plume during the spring and fall of 2008 have exceeded expectations of signal strength, solidifying the existence of complex organic material and offering answers to many questions arising from the initial encounter. New analysis techniques have been developed to take advantage of the multiple data sets, enabling a more thorough investigation. INMS data from all relevant observations are combined and presented here for a comprehensive analysis of the neutral composition of Enceladus' plume.