Initial Results from the Rosetta LAP Instrument

This work is based on the commissioning data from the Rosetta Langmuir probe instrument (aka LAP) received in May 7-11, 2004. At rst, we worked on ESA's hierarchy and structure for the LAP data and wrote a base code to browse through these data and display them in a typical cur-rent vs bias voltage curve. Then we improved the graphical functionalities and features of this browsing software now called PDS_browser, and added a model to t the instrument measure-ments in order to evaluate its performance and derive some physical parameters. The software indeed allowed to get some realistic values for the spacecraft potential, and the different current contributions as well as for the temperatures. Finally, when plotted against time, the data showed a predictable behaviour and the different parameters seem to be well correlated amongst each other though they don't really match with measurements from the ACE spacecraft, probably because the properties of the solar wind are not homogeneous on such a large scale