The Puzzle of the Flyby Anomaly

TL;DR

The paper discusses the flyby anomaly, an unexplained energy change observed during spacecraft gravity assists, highlighting gaps in current understanding and exploring potential explanations.

Contribution

It provides a summary of recent observations of the flyby anomaly and discusses possible physical explanations for this unexplained phenomenon.

Findings

Multiple spacecraft experienced unexpected energy changes during Earth flybys.

Standard astrodynamics methods cannot fully explain the observed anomalies.

The paper suggests potential avenues for resolving the flyby anomaly puzzle.

Abstract

Close planetary flybys are frequently employed as a technique to place spacecraft on extreme solar system trajectories that would otherwise require much larger booster vehicles or may not even be feasible when relying solely on chemical propulsion. The theoretical description of the flybys, referred to as gravity assists, is well established. However, there seems to be a lack of understanding of the physical processes occurring during these dynamical events. Radio-metric tracking data received from a number of spacecraft that experienced an Earth gravity assist indicate the presence of an unexpected energy change that happened during the flyby and cannot be explained by the standard methods of modern astrodynamics. This puzzling behavior of several spacecraft has become known as the flyby anomaly. We present the summary of the recent anomalous observations and discuss possible ways to resolve this puzzle.