The "Pioneer effect" as a manifestation of the cosmic expansion in the   solar system
  It is proposed that the recently reported anomalous acceleration acting on the Pioneers spacecrafts should be a consequence of the existence of some local curvature in light geodesics when using the coordinate speed of light in an expanding spacetime. This suggests taht this "Pioneer effect" is nothing else but the detection of cosmological expansion in the solar system. 
Jose-Luis Rosales and Jose-Luis Sanchez-Gomez