The B-2 Spirit is a multi-role bomber capable of delivering both conventional and nuclear munitions. A dramatic leap forward in technology, the bomber represents a major milestone in the U.S. bomber modernization program. The B-2 brings massive firepower to bear, in a short time, anywhere on the globe through previously impenetrable defenses. Its low-observable, or "stealth," characteristics give it the unique ability to penetrate an enemy's most sophisticated defenses and threaten its most valued, and heavily defended targets.
The B-2's low observability is derived from a combination of reduced infrared, acoustic, electromagnetic, visual and radar signatures. These signatures make it difficult for the sophisticated defensive systems to detect, track and engage the B-2. Many aspects of the low-observability process remain classified; however, the B-2's composite materials, special coatings and flying-wing design all contribute to its "stealthiness".
On the 23rd of Feburary, 2008, a B-2 stealth bomber plunged to the ground shortly after taking off from an air base in Guam. This was the first time a Spirit has crashed. The aircraft was taking off with three others on their last flight out of Guam after a four-month deployment, part of a continuous U.S. bomber presence in the western Pacific. The crash was caused by moisture in its sensors. Water distorted the preflight readings in three of the plane's 24 sensors, making the aircraft's control computer force the B-2 to pitch up on takeoff, resulting in a stall and subsequent crash. Both pilots ejected safely just after the left wing made contact with the ground. There were no injuries on the ground or damage to buildings, and no munitions were on board.