title: Verification of Earth's "Pear Shape" Gravitational Harmonic.
abstract: 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.
authors.forename: C J
authors.initials: CJ
authors.lastname: Cohen
authors.forename: R J
authors.initials: RJ
authors.lastname: Anderle