in range of aircraft from the Japanese mainland. The fast carrier force was tasked with attacking airfields in southern Japan until they were incapable of launching effective airborne opposition to the impending invasion. The fast carrier force departed for Japan from Ulithi on 14 March. On 18 March, she launched an attack from a position southeast of the island of Kyūshū. The attack targeted airfields on Kyūshū, as well as ships of the Japanese fleet in the harbors of Kobe and Kure, on southern Honshū. The Japanese located the American task force on 21 March, sending 48 planes to attack the ships. Twenty-four fighters from the task force intercepted and shot down all the Japanese aircraft. Indianapolis was assigned to Task Force 54 (TF 54) for the invasion of Okinawa. When TF 54 began pre-invasion bombardment of Okinawa on 24 March, Indianapolis spent 7 days pouring 8-inch shells into the beach defenses. During this time, enemy aircraft repeatedly attacked the American ships. Indianapolis shot down six planes and damaged two others. On 31 March, the day before the Tenth Army (combined U.S. Army and U.S. Marine Corps) started its assault landings, the Indianapolis lookouts spotted a Japanese Nakajima Ki-43 "Oscar" fighter as it emerged from the morning twilight and dived vertically towards the bridge. The ship's 20 mm guns opened fire, but within 15 seconds the plane was over the ship. Tracers converged on it, causing it to swerve, but the pilot managed to release his bomb from a height of , then crashing his plane into the sea near the port stern. The bomb plummeted through the deck, into the crew's mess hall, down through the berthing compartment, and through the fuel tanks before crashing through the keel and exploding in the water underneath. The concussion blew two gaping holes in the keel which flooded nearby compartments, killing nine crewmen. The ship's bulkheads prevented any progressive flooding. Indianapolis, settling slightly by the stern and listing to port, steamed to a salvage ship for emergency repairs. Here, inspection revealed that her propeller shafts were damaged, her fuel tanks ruptured, and her water-distilling equipment ruined. Indianapolis then steamed under her own power to the Mare Island Naval Shipyard for repairs. Transporting nuclear weapons After major repairs and an overhaul, Indianapolis received orders to undertake a top-secret mission of the utmost significance to national security: to proceed to Tinian island carrying the