Search for a Standard Explanation of the Pioneer Anomaly

TL;DR

This paper investigates the Pioneer anomaly, analyzing thermal systematics to determine if onboard heat effects can explain the observed acceleration, and finds current models insufficient to account for the anomaly.

Contribution

It critically evaluates existing thermal models and proposes new approaches to better understand the Pioneer anomaly's origin.

Findings

Thermal models so far are not supported by data

The anomaly persists beyond thermal explanations

Further investigation methods are suggested

Abstract

The data from Pioneer 10 and 11 shows an anomalous, constant, Doppler frequency drift that can be interpreted as an acceleration directed towards the Sun of a_P = (8.74 \pm 1.33) x 10^{-8} cm/s^2. Although one can consider a new physical origin for the anomaly, one first must investigate the contributions of the prime candidates, which are systematics generated on board. Here we expand upon previous analyses of thermal systematics. We demonstrate that thermal models put forth so far are not supported by the analyzed data. Possible ways to further investigate the nature of the anomaly are proposed.