Using Early Data to Illuminate the Pioneer Anomaly

TL;DR

Analysis of early Pioneer spacecraft data reveals an unexplained small acceleration towards the Sun, which could be due to systematic effects or new physics, highlighting the need for further detailed investigation.

Contribution

This paper emphasizes the importance of analyzing early data from Pioneer missions to better understand the Pioneer Anomaly and distinguish between systematic errors and potential new physics.

Findings

Detected a small, unmodeled acceleration towards the Sun.

Early data analysis could clarify the anomaly's origin.

Systematic effects have not been conclusively identified.

Abstract

Analysis of the radio tracking data from the Pioneer 10/11 spacecraft at distances between about 20 - 70 AU from the Sun has consistently indicated the presence of an unmodeled, small, constant, Doppler blue shift drift of order 6 \times 10^{-9} Hz/s. After accounting for systematics, this drift can be interpreted as a constant acceleration of a_P= (8.74 \pm 1.33) \times 10^{-8} cm/s^2 directed towards the Sun, or perhaps as a time acceleration of a_t = (2.92 \pm 0.44)\times 10^{-18} s/s^2. Although it is suspected that there is a systematic origin to this anomaly, none has been unambiguously demonstrated. We review the current status of the anomaly, and then point out how the analysis of early data, which was never analyzed in detail, could allow a more clear understanding of the origin of the anomaly, be it a systematic or a manifestation of unsuspected physics.