München 2009 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 14: Experimente zur Gravitation I
GR 14.5: Talk
Thursday, March 12, 2009, 18:45–19:05, A214
New precise method for thermal recoil force computation with application to the Pioneer anomaly — •Benny Rievers1, Claus Lämmerzahl1, and Hansjörg Dittus2 — 1Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation ZARM Universität Bremen 28359 Bremen — 2DLR Institut für Raumfahrtsysteme Robert-Hooke-Str. 7 28359 Bremen
For high precision geodesic and fundamental physics missions such as LISA, LISA pathfinder and MICROSCOPE, exact knowledge of the disturbances is crucial for mission success. An important perturbation originates from non-symmetric heat dissipation. At ZARM a method for the exact computation of the resulting disturbance force has been developed. The method is based on the modeling of the spacecraft geometry in finite elements (FE) and raytracing. A thermal FE analysis is conducted to compute a surface temperature distribution of the craft. The FE model includes the geometry, material parameters and all contraints (conduction, radiation, environment) for the FE solution. The results of the analysis are imported into a raytracing algorithm which computes the resulting recoil force including reflection, absorption and shadowing effects. As a test case the Pioneer 11 radio isotopic thermal generators (RTG) are processed. The results point out that a more detailed thermal analysis for the whole craft is necessary as the simplified test case shows a recoil force that is non-negligible with respect to the Pioneer Anomaly. This analysis is ongoing and will enable the high precision computation of the Pioneer 11 heat dissipation perturbation.