sentence1: by imposing that it is the source of the anomalous pioneer acceleration , to calculate the perihelion rates of the inner planets of the solar system for which estimates of their extra-advances accurate enough for our purposes exist .
sentence2: by imposing that it is the source of the anomalous pioneer acceleration , to calculate the perihelion rates of the inner 3 planets of the solar system for which estimates of their extra-advances accurate enough for our purposes exist .