Physical sciences: Perturbations of Pioneer 6 telemetry signal during solar occultation

Abstract

ATTENTION has been drawn recently to unexplained perturbations in the telemetry signal of Pioneer 6 (2,300 MHz) during solar occultation. The results¹ shown in Fig. 1 present the following odd features: (1) An anomalous redshift is added to a normal linear redshift due to the spacecraft oscillator. This residual redshift which is symmetrical with respect to the centre of the Sun is of the order of z = 5.18⁻⁸ at four solar radii. (2) The bandwidth increases sharply when the telemetry signal grazes the Sun. (3) There are some extremely sharp pulses in the bandwidth. In Fig. 2 we show that these pulses are clearly associated with a sharp increase of the redshift and correspond to solar flares.