Operational Tools and Data Management for OSIRIS-REx Optical Navigation

Abstract

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft was launched in September 2016 and arrived at its target, near-Earth asteroid (101955) Bennu in late 2018. After executing nearly two years of multi-phase proximity operations navigation and mapping campaigns, on October 20, 2020 OSIRIS-REx successfully performed the Touch-And-Go (TAG) maneuver to become the first American mission to collect a sample from an asteroid. As Bennu is one of the smallest objects ever to be visited by a planetary spacecraft, the mission presented many navigational challenges, and optical navigation (OpNav) techniques were essential to the successful execution of the mission. The specific challenges of OSIRIS-REx required nimble OpNav planning, robust data management, and quick, automated analyses and data-product delivery capabilities. In addition to the two primary image processing tools, centroid-based and landmark-based OpNav, a host of support and planning tools and procedures were developed. The multi-year operations timeline, fast maneuver cadence, and multi-phase nature of proximity operations for OSIRIS-REx motivated a streamlined and reactive image planning process. A suite of tools was developed to ensure that the mission navigation requirements were continually satisfied. On approach, the Op-N av Opportunity Analyzer (OpOpp) was used to deconflict the imaging schedule with interference from bright background stars. In-flight instrument calibration was performed using an in-house distortion calibration toolset. An Exposure Time Calculator was used to determine optimal exposure times and verify that the images would produce sufficient OpNav image data. Additionally, Fly-Point-Shoot (FPS) software was used to analyze and mitigate the effect of trajectory and pointing uncertainties on image planning and coverage. This paper describes in further detail the operational challenges of the OSIRIS-REx OpNav subsystem, as well as the tools, procedures, and strategies developed to ensure the satisfaction of navigation requirements.