Thermal dissipation force modeling with preliminary results for Pioneer 10/11
- Paper number
IAC-08.C1.7.3
- Author
Mr. Benny Rievers, ZARM - University of Bremen, Germany
- Coauthor
Mrs. Meike List, ZARM - University of Bremen, Germany
- Coauthor
Mrs. Stefanie Bremer, ZARM - University of Bremen, Germany
- Year
2008
- Abstract
The dissipation of waste thermal energy can produce disturbance forces on spacecraft surfaces if the energy is not dissipated in a symmetric pattern. This force can be computed for a single plate surface element as the quotient of the radiated power and the speed of light. Depending on mission and spacecraft design the resulting surface forces have to be included into the disturbance budget.
At ZARM (Center of Applied Space Technology and Microgravity) a ray tracing algorithm was developed that allows to compute the resulting force for complex spacecraft geometries. The method is based on the modeling of the spacecraft geometry in finite elements (FE). Using a FE-solver the surface temperature map of the satellite can be derived with geometry, material parameters and heat sources/sinks as constraints. The outgoing total radiation force is computed including reflection and absorption between all elements of the model.
As an example for the method the geometry of the radio isotope thermal generators (RTG) of Pioneer 11 is processed in the ray tracer. The temperature map is derived with the FE-program ANSYS using temperature telemetry for validation. In a preliminary analysis it is shown that the force produced by the two RTGs and the interaction between the satellite bus and the RTGs produce an acceleration in the range of 2 · 10 −10 m/ s 2, thus explaining roughly a forth of the so called Pioneer anomaly.
As next steps the dissipation force generated by the other parts of the spacecraft will be calculated in detail. Thus we will be able to evaluate how much of the current Pioneer residuals can be explained with the thermal dissipation force. After the analysis of the Pioneer 11 mission it is planned to use the ray tracing method on present missions such as the Microscope mission.
- Abstract document
- Manuscript document
IAC-08.C1.7.3.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.