Verification of Earth's "Pear Shape" Gravitational Harmonic.
Predictions of the orbit of the Transit 1B satellite were systematically in error until account was taken of a third-order gravitational harmonic. The amplitude deduced for this harmonic by O'Keefe from the Vanguard I orbit serves very well, even though the orbits and the methods of observation and orbit fitting for the two satellites are quite different.
Cohen
C J
CJ
Anderle
R J
RJ