The contractor-operated post office at the Kennedy Space Center in Florida ceased operations on the 26th of September, 2023. There has been a post office at the KSC in one form or another since 1965. I would guess that most of its customers were space cover collectors. Near the bottom of this thread it mentions there were 663 items hand cancelled on closing day. I found out about the closure at the last minute and managed to get this cover down there for cancellation on the last day.