Integrated Solar Upper Stage (ISUS) mission trades

Solar thermal propulsion and propulsion/power systems were identified as key technologies in the operational effectiveness and cost comparison study (OECS) sponsored by Phillips Laboratory (PL). These technologies were found to be pervasively cost effective with short transfer times and very good performance across a wide range of missions. The on-going Integrated Solar Upper Stage (ISUS) Program sponsored by PL represents development of a solar thermal propulsion/power (bimodal) system. As part of this effort, mission trades are being conducted to further define the ISUS system for geosynchronous equatorial orbit (GEO), high Earth orbit (HEO-Molniya class), and mid Earth orbit (MEO-GPS class) missions. These trades will consider launch vehicles ranging in size from a LLV3 to an Atlas IIAS that insert the ISUS into low Earth orbit (LEO). These trades will be used to define the ISUS system for the planned Engine Ground Demonstration, a space demonstration mission, and as a future operational system