9-3. Galileo and Ulysses Missions Safety Analysis and Launch Readiness Status M. JOSEPH CORK & JAMES A. TURI Summary The Galileo and Ulysses Missions are working their way up the Space Shuttle launch manifest for scheduled launches in October 1989 and October 1990, respectively. These missions, originally approved in 1978-79, have undergone several programmatic changes paralleling the development of upper stage booster rockets for use with the Space Shuttle (Space Transportation System (STS)). Galileo will explore the Jupiter system and Ulysses will fly by Jupiter en route to a polar orbit of the sun. Both spacecraft are powered by general purpose heat source (GPHS) radioisotope thermoelectric generators (RTGs). The GPHS-RTG developed by the United States Department of Energy (DOE) is a successor to RTGs used on previous missions. The Galileo and Ulysses missions' programmatic changes have impacted the safety testing and analyses required as part of the launch approval process. As a result of the Challenger accident and subsequent mission reprogramming, the missions' safety analysis had to be repeated. The change from the Centaur to the inertial upper state (IUS) booster rocket for the mission required a new assessment and definition of possible STS/IUS accident scenarios. The Galileo project undertook an extensive Earth-avoidance analysis because the solid propellant IUS mandated a new trajectory design using two Earth flybys. The Department of Energy completed a series of RTG tests using simulated solid propellant case fragments. The Final Safety Analysis Report (FSAR) was released in January 1989 for review by the presidentially mandated Interagency Nuclear Safety Review Panel (INSRP). In addition to presenting an overview of the safety analysis status for the Galileo and Ulysses missions, this paper presents a brief review of the missions' objectives and design approaches, RTG design characteristics and development history, and a description of the safety analysis process. Introduction Launch of the Galileo mission to Jupiter in October 1989 will mark the re-entry of the United States into outer planet exploration after a long hiatus. The spacecraft, named after Galileo Galilei, the discoverer of Jupiter's moons, will carry an array of advanced scientific instruments designed to elucidate the details of Jupiter's structure and the geography and mechanics of its principal satellites. On its complex path to Jupiter, M. Joseph Cork, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA; James A. Turi, Office of Nuclear Energy, US Department of Energy NE-53, Washington, DC, 20545, USA. Paper number IAF-ICOSP89-9-3.
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