Abstract

Radiometric data from the Pioneer 10 and II spacecraft indicate an apparent, constant skewing between the predicted and observed Doppler shifts. This offset has been attributed to a possible acceleration of 8.0 x 10^-8 cm/s² directed toward the sun for both craft. Any potential gravitometric models and systemic problems seem to fail in explaining this discrepancy. The value of the observed anomalous shift is shown to equal the difference between the calculated values for Newtonian and special relativistic Doppler expressions. The primary difference between these two equations is the time-dilation term of special relativity. For there to be a systemic problem in the equipment that exactly matches the presumed special relativistic Doppler time-dilation offsets for the specit1c velocities of the Earth and the Pioneer spacecraft would be a coincidence beyond comprehension. The anomalous signals seem to indicate a preference for the Newtonian values and a det1ciency of the relativistic Doppler corrections rather than any new gravitational physics. If proved correct, these results would place severe constraints on the applicable domain of special relativity.