The Anomalous Acceleration of the Pioneer Spacecrafts

TL;DR

The Pioneer anomaly is an unexplained constant acceleration towards the Sun observed in Pioneer spacecrafts, prompting investigations into potential new physics or forces in the outer Solar System.

Contribution

This paper reviews the Pioneer anomaly, consolidates observational data, and discusses the challenges in explaining the unexplained acceleration.

Findings

Confirmed the anomaly is not due to data handling errors

Multiple analyses agree on the acceleration magnitude

Standard physics explanations have been inconclusive

Abstract

Radiometric data from the Pioneer 10 and 11 spacecrafts have revealed an unexplained constant acceleration of a_A = (8.74 +/- 1.33) x 10^(-10) m s^(-2) towards the Sun, also known as the Pioneer anomaly. Different groups have analyzed the Pioneer data and have got the same results, which rules out computer programming and handling errors. Attempts to explain this phenomenon arguing intrinsic causes on-board the spacecrafts failed or have lead to inconclusive results. Therefore, the Pioneer anomalous acceleration has motivated the interest of researchers to find out explanations that could bring insight upon the forces acting in the outer Solar Systems or a hint to discover new natural laws.