The Flyby Anomaly

Is the physics within the Solar system really understood? discusses the flyby anomaly as well as the Pioneer anomaly and others. Simulation of the flyby anomaly by means of an empirical asymmetric gravitational potential with definite spatial orientation explores this anomaly and explains:

During several Earth flybys carried out since 1990, some spacecrafts have experienced an unexpected and until now unexplained anomalous velocity increase. This phenomenon is called the flyby anomaly and looks like the effect of an instantaneous acceleration of the spacecraft at the time of closest approach to Earth.