The primary target was to be the Kokura Arsenal, with the seaport city of Nagasaki as the alternative. Bockscar took off on 9 August, with Fat Man on board. This time, the primary target of Kokura was obscured by dense smoke left over from the earlier B-29 raid on nearby Yawata, and the bombardier could not pinpoint the specified aiming point despite three separate runs. So Sweeney turned to the secondary target, Nagasaki. There were clouds over Nagasaki as well, and a couple of runs over the target had to be made before the bombardier could find an opening in the clouds. At 11:00 am, Fat Man was released from the aircraft and after a long descent, the bomb exploded. The yield was estimated at 22 kilotons of TNT. Approximately 35,000 people died at Nagasaki from the immediate blast and fire. After releasing the bomb, Sweeney was forced to divert to Okinawa because of a problem with a fuel transfer pump, and because of the long flight with multiple bomb runs and circling for better weather. There was not even enough fuel left to fly to Iwo Jima. After refueling on Okinawa, the B-29 returned to Tinian. The Japanese Emperor ordered that the government accept the Allied terms of surrender at once. It took time for the full details to be worked out, and there was a very real danger that some elements of the Japanese military would still not accept surrender, and might attempt a military coup d'état, even against their Emperor. In the meantime, conventional bombing of Japanese targets still continued, with a record number of 804 B-29s hitting targets in Japan on 14 August. On the morning of 15 August, the Emperor broadcast by radio his command of Japan's surrender in an address to his nation. Practically none of his subjects had never heard his voice before. All further offensive operations against Japan ceased after the Emperor's broadcast. After that time, most of the B-29s in the Pacific were diverted to missions of mercy, dropping food and clothing to thousands of Allied prisoners of war held in Japan, China, Manchuria, and Korea. 1066 B-29s participated in 900 missions to 154 camps. Some 63,500 prisoners were provided with 4470 tons of supplies. These flights cost eight B-29s lost by accidents, with 77 crew members aboard. The Japanese surrender was formally signed on 2 September 1945, aboard the huge battleship "USS Missouri" in Tokyo Bay, bringing the Pacific War to an end.