The Quest to Understand the Pioneer Anomaly

TL;DR

This paper reviews the Pioneer 10/11 missions and the unexplained anomalous acceleration observed, discussing ongoing efforts to identify its cause, including data analysis and potential new missions.

Contribution

It provides a comprehensive review of the Pioneer anomaly and outlines current research directions to determine its origin, highlighting the importance of detailed data analysis and future mission planning.

Findings

An unmodeled acceleration of ~8 x 10^{-8} cm/s^2 was observed.

Radiant heat is a likely but unconfirmed cause.

Multiple efforts are underway to resolve the anomaly.

Abstract

The Pioneer 10/11 missions, launched in 1972 and 1973, and their navigation are reviewed. Beginning in about 1980 an unmodeled force of ~ 8 x 10^{-8} cm/s^2 appeared in the tracking data, it later being verified. The cause remains unknown, although radiant heat remains a likely origin. A set of efforts to find the solution are underway: a) analyzing in detail all available data, b) using data from the New Horizons mission, and c) considering an ESA dedicated mission.