Wednesday plenary 2: Contributed talk
When
Where
Theme: Software, tools and standards for Solar System, heliophysics, and planetary research
NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer; OREx) spacecraft successfully accomplished its primary mission objective to retrieve a sample from the surface of the near-Earth asteroid (101955) Bennu on October 20, 2020 (Lauretta et al., 2022). The OREx team had been preparing for this event since the spacecraft’s arrival at Bennu in December of 2018 by mapping the asteroid and characterizing its geological, chemical, and physical properties. Mapping continued after sample collection to quantify surface changes resulting from contact between the spacecraft and Bennu.
The spacecraft departed Bennu in May of 2021, and the sample is scheduled to return to Earth on September 24, 2023. Image processing, photogrammetric control, and mosaicking were accomplished with a modified version of the Integrated Software for Imagers and Spectrometers (ISIS) planetary cartography package, developed and maintained by the OREx team. In the control process, images acquired by the OSIRIS-REx Camera Suite were registered to and orthorectified onto tessellated shape models created by the OREx team. The shape models are global in coverage and range from 80 cm to 5 cm average ground sample distance. OREx ISIS improves the execution of critical tasks in the cartographic process such as precision ray tracing, manual and automated image measurement, accurate determination of terrain-relative photometric/observation angles and characteristics, orthorectification, and the detection of occlusions and shadows.
These improvements in operational efficiency and mapping accuracy provide enhanced support not only for irregularly shaped bodies such as asteroids and comets, but for small-body mapping in general, and for bodies such as the Moon, for which high-resolution shape models and imagery may be available. Validated over more than three years of proximity operations at Bennu, ISIS enabled the generation of a global basemap and regional image mosaics at resolutions from ~6 cm/pixel to 1 mm/pixel. These products were crucial to the sample-site selection process and the sample acquisition itself. We will submit our enhancements to the public version of ISIS and release them to the scientific community in the form of a standalone shared library developed in C++ as the Planetary Shape Model Ray Tracing System (PSMRTS).
Additionally, we will provide a C-like interface that provides access to many different languages such as C, Python, Rust, and others. The current version of our ISIS implementation supports three publicly available ray tracing libraries. These libraries are the NAIF DSK, the Bullet Physics SDK, and the Intel Embree ray tracing systems.
This work is supported by NASA under contract NNM10AA11C issued through the New Frontiers Program. Lauretta, D.S., et al., 2022. Spacecraft sample collection and subsurface excavation of asteroid (101955) Bennu. Science. 377 (6603), 285–291. doi.org/10.1126/science.abm101