Maneuver strategies for the extended Pioneer 11 Jupiter/Saturn mission

The Jupiter-bound Pioneer 11 spacecraft was launched in April 1973, eight months before the Jupiter encounter of the front-running spacecraft, Pioneer 10. Near-Earth maneuvers placed Pioneer 11 on an interim flight path designed to retain a later retargeting capability to repeat the Pioneer 10 flyby geometry or encounter a wide variety of alternate Jupiter aimpoints, including one resulting in an extended five-year trajectory to Saturn. Pioneer 11 was retargeted to this aimpoint in April 1974, subsequent to the successful Pioneer 10 encounter in December 1973. This paper presents the retargeting and trimming maneuver strategies necessary to assure a productive Pioneer 11 Jupiter encounter in early December 1974, followed by a Saturn encounter in late 1979.