On the possible onset of the Pioneer anomaly

Michael R Feldman,John D Anderson

doi:10.1142/s0218271815500662

Michael R Feldman, John D Anderson

Open Access

https://doi.org/10.1142/s0218271815500662

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Abstract

We explore the possibility that the observed onset of the Pioneer anomaly after Saturn encounter by Pioneer 11 is not necessarily due to mismodeling of solar radiation pressure but instead reflects a physically relevant characteristic of the anomaly itself. We employ the principles of a recently proposed cosmological model termed "the theory of inertial centers" along with an understanding of the fundamental assumptions taken by the Deep Space Network (DSN) to attempt to model this sudden onset. Due to an ambiguity that arises from the difference in the DSN definition of expected light-time with light-time according to the theory of inertial centers, we are forced to adopt a seemingly arbitrary convention to relate DSN-assumed clock-rates to physical clock-rates for this model. We offer a possible reason for adopting the convention employed in our analysis; however, we remain skeptical. Nevertheless, with this convention, one finds that this theory is able to replicate the previously reported Hubble-like behavior of the "clock acceleration" for the Pioneer anomaly as well as the sudden onset of the anomalous acceleration after Pioneer 11 Saturn encounter. While oscillatory behavior with a yearly period is also predicted for the anomalous clock accelerations of both Pioneer 10 and Pioneer 11, the predicted amplitude is an order of magnitude too small when compared with that reported for Pioneer 10.

Highlights

First reported in Ref. 1 and detailed in Ref. 2, the Pioneer anomaly refers to an unmodeled, blueshifted frequency drift with near uniform rate of change observed in the Deep Space Network (DSN) residuals for both Pioneer 10 and Pioneer 11M
While there have been many suggestions and avenues of exploration for what could possibly account for this discrepancy,[2,3] after a recent analysis of an extended set of DSN frequency data, there appears to be significant support for the origin of this anomaly as a recoil force associated with an anisotropic emission of thermal radiation off the spacecrafts due to the waste heat emitted by the radioisotope thermoelectric generators (RTGs) onboard.[4,5,6,7,8,9,10,11,12]
It would appear from these analyses that the Pioneer anomaly, if caused by physics not modeled by the DSN and not an unaccounted-for acceleration due to the intrinsic structure of the spacecrafts, would have to affect only the Doppler residuals calculated by the DSN and not the actual paths of our Solar System objects relative to one another

Summary

Introduction

First reported in Ref. 1 and detailed in Ref. 2, the Pioneer anomaly refers to an unmodeled, blueshifted frequency drift with near uniform rate of change observed in the Deep Space Network (DSN) residuals for both Pioneer 10 and Pioneer 11. 13–16) remains an open source of concern after the same analysis of the extended data set appeared to be consistent with the possibility of this behavior, taken to likely be the result of mismodeling of solar radiation pressure.[17] other works independent of articles concerned with a thermal explanation effectively showed that the Pioneer anomaly as an extra physical acceleration directed towards the Sun acting upon all Solar System bodies would be inconsistent with the observed motion of planets, spacecrafts and other celestial bodies.[15,16,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32] It would appear from these analyses that the Pioneer anomaly, if caused by physics not modeled by the DSN and not an unaccounted-for acceleration due to the intrinsic structure of the spacecrafts, would have to affect only the Doppler residuals calculated by the DSN and not the actual paths of our Solar System objects relative to one another We will emphasize this point later in our discussion and argue that, under our proposed mechanism, objects in the Solar System will continue to orbit the Sun in the same manner as predicted by general relativity and expected by the DSN.

Results and Discussion

Stationary observer treatment

Predictions using data from HORIZONS

Conclusion