By 2251, Sulu was living on Hafjian, a high-gravity planet where the inhabitants were forced to wear Lieber exoskeletons. Years later, Dr. McCoy was concerned that this might cause problems for Sulu after he turned 70. By 2252, Sulu was once again living on Ganjitsu, when he snuck aboard the USS Aerfen to meet Captain Hunter. Sulu was discovered and given a guided tour of the starship. (TOS novel: Enterprise: The First Adventure)