The Contribution of Thermal Effects to the Acceleration of the Deep-Space Pioneer Spacecraft

TL;DR

This paper presents a method to accurately compute thermal radiation effects on the Pioneer spacecraft, demonstrating that thermal forces fully account for the observed anomalous acceleration.

Contribution

It introduces a reliable computational approach for thermal momentum transfer and confirms thermal effects as the sole cause of Pioneer anomaly.

Findings

Thermal effects explain the entire Pioneer anomalous acceleration.

The model estimates the acceleration's time evolution due to thermal effects.

Thermal conduction between spacecraft components is negligible.

Abstract

A method for the computation of the radiative momentum transfer in the Pioneer 10 & 11 spacecraft due to the diffusive and specular components of reflection is presented. The method provides a reliable estimate of the thermal contribution to the acceleration of these deep space probes and allows for a Monte-Carlo analysis from which an estimate of the impact of a possible variability of the parameters. It is shown that the whole anomalous acceleration can be explained by thermal effects. The model also allows one to estimate the expected time evolution of the acceleration due to thermal effects. The issue of thermal conduction between the different components of the spacecraft is discussed and confirmed to be negligible.