deployed as close air support for, and in proximity to, U.S. ground forces. The proximity to friendly forces require precision strikes from these aircraft that are not always possible with bomber aircraft. Their role is tactical rather than strategic, operating at the front of the battle rather than against targets deeper in the enemy's rear. The Air Force is currently running the OA-X experiment, with the intent to procure an off-the-shelf light attack aircraft. Current USAF attack aircraft are operated by Air Combat Command, Pacific Air Forces, and Air Force Special Operations Command. A-10C Thunderbolt II AC-130J Ghostrider B – Bomber US Air Force bombers are strategic weapons, primarily used for long range strike missions with either conventional or nuclear ordnance. Traditionally used for attacking strategic targets, today many bombers are also used in the tactical mission, such as providing close air support for ground forces and tactical interdiction missions. All Air Force bombers are under Global Strike Command. The service's B-2A aircraft entered service in the 1990s, its B-1B aircraft in the 1980s and its current B-52H aircraft in the early 1960s. The B-52 Stratofortress airframe design is over 60 years old and the B-52H aircraft currently in the active inventory were all built between 1960 and 1962. The B-52H is scheduled to remain in service for another 30 years, which would keep the airframe in service for nearly 90 years, an unprecedented length of service for any aircraft. The B-21 is projected to replace the B-52 and parts of the B-1B force by the mid-2020s. B-1B Lancer B-2A Spirit B-52H Stratofortress B-21 Raider C – Transport Transport aircraft are typically used to deliver troops, weapons and other military equipment by a variety of methods to any area of military operations around the world, usually outside of the commercial flight routes in uncontrolled airspace. The workhorses of the USAF airlift forces are the C-130 Hercules, C-17 Globemaster III, and C-5 Galaxy. The CV-22 is used by the Air Force for special operations. It conducts long-range, special operations missions, and is equipped with extra fuel tanks and terrain-following radar. Some aircraft serve specialized transportation roles such as executive or embassy support (C-12), Antarctic support (LC-130H), and AFSOC support (C-27J and C-146A). Although most of the US Air Force's cargo aircraft were specially designed with the Air Force in mind, some aircraft such as the C-12 Huron (Beechcraft Super King Air)