Sarn was a Federation colony world. In late 2365 or early 2366, the USS Grissom was ordered to Sarn to assist in repairing damage to the colony's fusion reactor. The mission team consisted of first officer Christine Parsons, chief of security Cray, science officer Chu'lak, and assistant chief engineer Katerina Mueller. Unfortunately, the core exploded during the course of the mission. While Parsons and Chu'lak both agreed that there was no way the team could have prevented this accident, Cray placed the blame on Mueller. This incident led to a great deal of enmity between the two officers throughout the rest of their service together. (NF short story: "Performance Appraisal")