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Lock on Target

For Astro-1 the only method of placing the IPS in optical hold was to achieve a successful IDOP. For Astro-2 this software limitation has been circumvented by designing a new tracking mode known as lock-on-target (LOT). In this mode each of the trackers is commanded to search its field and to acquire and lock onto the first star it finds without using any position or brightness criteria. The crew has identified the field using the HUT TV camera, so they know where the IPS is pointed, even if it doesn't. This permits the crew to then track targets with the IPS in optical hold no matter how the target acquisition was performed in the first place.