Jd. Anderson et al., INDICATION, FROM PIONEER-10 PIONEER-11, GALILEO, AND ULYSSES DATA, OFAN APPARENT ANOMALOUS, WEAK, LONG-RANGE ACCELERATION/, Physical review letters, 81(14), 1998, pp. 2858-2861
Radio metric data from the Pioneer 10/11, Galileo, and Ulysses spacecr
aft indicate an apparent anomalous, constant, acceleration acting on t
he spacecraft with a magnitude similar to 8.5 x 10(-8) cm/s(2), direct
ed towards the Sun. Two independent codes and physical strategies have
been used to analyze the data. A number of potential causes have been
ruled out. We discuss future kinematic tests and possible origins of
the signal.