The objective of this IRAD is to develop, implement, test and verify the 150x150 lunar gravity model for orbit determination (OD) and prediction on the FPGA during the fiscal year 2025. The goal of this task is to meet the Lunar Reconnaissance Orbiter (LRO) requirements for OD and prediction accuracy, which are 500 meters total position root mean squared (RMS) and 18 meters radial RMS for definitive ephemeris accuracy and predicted orbit accuracy less than 800 meters root sum squared (RSS) over an 84-hour prediction span.

For missions like the LRO, which needs a large lunar gravity model for accurate OD, the Flight Dynamics Facility (FDF) uses the Goddard Trajectory Determination System (GTDS) for OD on the ground. However, with the technological advancement and improvement of space qualified processors and field programmable gate arrays (FPGAs), we can move the OD of LRO-type missions to the spacecraft's onboard computer. This IRAD aims to implement hardware acceleration of the lunar gravity model to significantly improve the processing speed for onboard OD for future LRO-like missions.