A Possible Explanation of Anomalous Earth Flybys
  Doppler shift observations of several spacecrafts during near Earth flybys show an unexplained frequency shift. This shift is interpreted as an unexpected velocity change called Earth flyby anomaly. A theory of non-privileged reference frames is used to study the Doppler shift in such frames which are experimentally justified by the measured dipole anisotropy of the cosmic microwave background (CMB) in the solar system. The system in which the CMB is isotropic defines the privileged reference frame. The calculated frequency shift in non-privileged reference frames may give an explanation of the anomalous Earth flybys. 
Walter Petry