The black, bat-like B-2A Spirit is the silver bullet of US policy, reserved for use against targets of the highest priority. The B-2 is the costliest warplane ever built (around $900 million per copy), is difficult to maintain and is prone to trouble with the coating that provides much of its stealth.
The B-2 Spirit was developed as a low observable strategic bomber for the Cold War mission of attacking Soviet strategic targets. Composites are extensively used to provide a radar-absorbent honeycomb structure; the bomber has a minimal IR signature, does not contrail and uses its shielded APQ-181 radar only momentarily to identify a target just before attacking. The glass cockpit is usually flown by a crew of two. The aircraft has a quadruplex-redundant digital fly-by-wire system and highly advanced, classified electronic warfare system.
Six prototypes were funded and the first was rolled out on 22 November 1988. The B-2's first flight took place on 17 July 1991 the USAF implemented a set of treatments to rectify a shortfall in the B-2A's stealth capabilities.
The USAF had originally wanted 132 aircraft, but funding restrictions have seen the fleet completed with just 21 aircraft. The last of these was delivered on 14 July 2000 and is the AV-1 prototype upgraded to Block 30 standard. The first operational B-2A was delivered to the 509th Bomb Wing on 17 December 1993 and full initial operating capability came in April 1997.
Having progressed through the Block 10 and 20 standards of stealth, systems and weapons capability, the entire B-2A fleet will be brought to Block 30 standard with full weapons and stealth capabilities. The B-2A made its combat debut over Kosovo in 1999, employing the Joint Direct Attack Munition (JDAM) and other weapons to great effect. Although the USAF's B-2 force is garrisoned at Whiteman air force base, Missouri, the service has ambitious plans to operate the aircraft temporarily from forward bases like Guam and Diego Garcia.