Simulating Infrared Images of Asteroids and the Lunar Surface in Real-time for Testing Future Missions

Vision systems are well-established in mission studies to support spacecraft navigation and hazard detection to support safe and precise landings. Future missions may also use thermal cameras for navigation and guidance, sensing radiation in the infrared or near-infrared ranges, to obtain different or additional information from established vision-based systems. There are existing tools that generate realistic thermal simulations on relatively low-resolution models but are not in genuine real-time. To test and validate the thermal image processing algorithms being developed for future mission studies, a system to generate realistic thermal images in real-time for closed loops simulations would be an extremely useful tool. Extensive, processed thermal data of the Moon has been provided by the Lunar Reconnaissance Orbiter Diviner instrument and thermal models for the lunar surface have been derived from that data in the literature. Some thermal data from current missions to asteroids Bennu and Ryugu is also available and has been used for comparing the simulated images with the equivalent real thermal image data.
This paper describes the adaptation and extension of the thermal models and basic thermal physics to implement a real-time thermal renderer on a high-speed Graphical Processing Unit to generate representative thermal images of asteroids and the lunar and surface in real-time. The implementation has been incorporated within the established PANGU (Planet and Asteroid Natural scene Generation Utility) software package which is an established and validated tool designed to support testing and validation of vision-based guidance and navigation systems to extend the simulations to simulate thermal cameras.