Support for the Thermal Origin of the Pioneer Anomaly
Abstract
We investigate the possibility that the anomalous acceleration of the Pioneer 10 and 11 spacecraft is due to the recoil force associated with an anisotropic emission of thermal radiation off the vehicles. To this end, relying on the project and spacecraft design documentation, we constructed a comprehensive finiteelement thermal model of the two spacecraft. Then, we numerically solve thermal conduction and radiation equations using the actual flight telemetry as boundary conditions. We use the results of this model to evaluate the effect of the thermal recoil force on the Pioneer 10 spacecraft at various heliocentric distances. We found that the magnitude, temporal behavior, and direction of the resulting thermal acceleration are all similar to the properties of the observed anomaly. As a novel element of our investigation, we develop a parametrized model for the thermal recoil force and estimate the coefficients of this model independently from navigational Doppler data. We find no statistically significant difference between the two estimates and conclude that, once the thermal recoil force is properly accounted for, no anomalous acceleration remains.
 Publication:

Physical Review Letters
 Pub Date:
 June 2012
 DOI:
 10.1103/PhysRevLett.108.241101
 arXiv:
 arXiv:1204.2507
 Bibcode:
 2012PhRvL.108x1101T
 Keywords:

 04.80.y;
 95.10.Eg;
 95.55.Pe;
 Experimental studies of gravity;
 Orbit determination and improvement;
 Lunar planetary and deepspace probes;
 General Relativity and Quantum Cosmology;
 Astrophysics  Instrumentation and Methods for Astrophysics;
 Physics  Space Physics
 EPrint:
 5 pages, 4 figures, 3 tables, accepted to Phys. Rev. Letters