The Air Force bomber force in flight together. The B-2 Spirit is a multi-role bomber capable of delivering both conventional and nuclear munitions. The B-1B Lancer is a multi-role, long-range bomber, capable of flying intercontinental missions without refueling, then penetrating present and predicted sophisticated enemy defences. It can perform a variety of missions, including that of a conventional weapons carrier for theatre operations. Air Combat Command's B-52 Stratofortress is a long-range, heavy bomber that can perform a variety of missions. The bomber is capable of flying at high subsonic speeds at altitudes up to 50,000 feet. It can carry nuclear or conventional ordnance with worldwide precision navigation capability.