The Mission System Architecture for Planned SPHEREx Operations

The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) mission will perform the first near-infrared all-sky spectral survey from Low Earth Orbit. During the 25 months of scheduled survey operations, SPHEREx will complete four all-sky surveys. The Mission System (MS) ground element is responsible for the planning and execution of operations for the SPHEREx satellite. Design of the SPHEREx MS architecture leverages WISE/NEOWISE mission operations heritage and the operational history of the Ball Configuration Platform (BCP)-100 spacecraft bus. The Mission System design also accounts for unique programmatic, technical, and science needs of the mission, especially its optical instrument. Salient features and unique challenges to designing the SPHEREx Mission System include: no onboard propulsion, use of NASA's Near Space Network Direct-to-Earth Ground Station and communication services, and tight slewing and pointing requirements for optical instrument safety and survey operations. On SPHEREx, the MS element is composed of six ground-based subsystems. Operations (OPS) covers the Mission Operation System (MOS) which consists of the people, processes, and procedures. Ground Data System (GDS) covers the networking and computing components required to support mission operations. Navigation (NAV) covers the software tools required for orbit prediction and reconstruction. Pointing Generation, Simulation, and Operations (PGSO) covers the Pointing Plan Generation & Simulation (PGEN) software, including the Waypoint Design Tool for continuous safe pointing. Sequencing (SEQ) covers command sequencing generation tools. Last but not least, SPHEREx Telemetry, Command and Communication Subsystem (STCCS) enables automated communication pass execution, and provides the Commanding uplink and Telemetry receipt software and services at the Mission Support Area. In describing the MS elements, the development of the associated interfaces, operational agreements, and supporting partner services are also presented.