in hopes of crushing the newly landed force and its naval support. The force refueled at Rabaul in preparation for the coming battle. Halsey lacked comparable surface forces to oppose this fresh challenge. His main surface strength, two battleships and a number of cruisers, had been transferred to the Central Pacific to support the upcoming invasion of Tarawa. The only forces at hand were the carrier airgroups of and . These would have been considered a potent force for a battle at sea, but Rabaul was a heavily fortified port with five airfields and extensive anti-aircraft batteries. Navy aviators had termed it "a hornet's nest". With the exception of the surprise raid at Pearl Harbor, no attack against such a formidable land target had been attempted by carrier aircraft. As such it was considered a highly dangerous mission for the aircrews and placed the carriers themselves at risk. Halsey later said the threat that the Japanese cruiser force at Rabaul posed to his landings at Bougainville was "the most desperate emergency that confronted me in my entire term as ComSoPac." With the fate of the landing in the balance, Halsey ordered his carriers, under command of Rear-Admiral Frederick Sherman, to steam north through the night of 4–5 November to get within range of Rabaul for a daybreak raid on the base. Approaching behind the cover of a weather front, Sherman launched all 97 of his available aircraft against the target, leaving no aircraft behind for combat air patrol over his ships. The aircrews were ordered to damage as many warships as possible, rather than attempting to achieve a sinking. Aircraft from airfields on Barakoma and the recently captured Vella Lavella were sent out to sea to rendezvous with the carrier force to provide it with some measure of protection. The daybreak Navy air bombing of Rabaul was followed up an hour later with an Army Air Force raid by 27 B-24 Liberator heavy bombers of the Fifth Air Force, escorted by 58 P-38s. By the end of the attacks six of the seven Japanese cruisers at Rabaul had been damaged, four of them heavily. suffered near misses by three bombs that caused severe damage and killed 22 crewmen, including her captain. was hit by one bomb above one of her engine rooms, causing heavy damage and killing 70 crewmen. was hit by one 500 lb bomb and set afire, causing