Small Neptune orbiter using aerocapture

Abstract

Following the successful fly-by reconnaissance of the outer planets achieved by the Pioneer and Voyager spacecraft, the next logical step in planetary exploration involves the long-term, orbital observations of these planets. The Galileo spacecraft is the first such mission to accomplish this goal. The recently-completed Mission to the Solar System Road Map calls for a significant effort to be devoted to future outer planet exploration missions. However, NASA’s current strategy for future mission design requires that planetary exploration be accomplished at a significantly lower cost than previous missions. This implies that future missions will be characterized by small spacecraft launched with low cost launch vehicles and operated with minimal ground operations. These pressures create substantial challenges for developers of such missions. Missions to the outer planets escalate these challenges even further due to the large distances involved. In the face of these pressures, moreover, these missions are expected to be high science value, high data return missions. To resolve the apparent conflict between needs and capabilities, a totally new approach is necessary. The study described in this paper is one conducted at JPL over the last year to assess the feasibility of conducting an orbital mission to Neptune consistent with modern challenges to cost and mission capability. For this mission, aerocapture is a critical enabling maneuver and this paper will present a description of that maneuver, the supporting design methodologies and the necessary thermal protection system.