Equation 8 deals with the Pioneer Anomaly.
https://en.wikipedia.org/wiki/Pioneer_anomaly
As you can see this remains a controversial topic. The degree of thermal recoil involved in the anomalous deceleration seems the most disputed point.
HC predicts a deceleration (A) of 7.317 e-10 metres/second squared. And this seems close to the residual deceleration after the effects of thermal recoil appear to have declined due to cooling.
