Along with the B-52 and B-1B, the B-2 provides the penetrating flexibility and effectiveness inherent in manned bombers. 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. Its capability to penetrate air defenses and threaten effective retaliation provide a strong, effective deterrent and combat force well into the 21st century.

The revolutionary blending of low-observable technologies with high aerodynamic efficiency and large payload gives the B-2 important advantages over existing bombers. Its low-observability provides it greater freedom of action at high altitudes, thus increasing its range and a better field of view for the aircraft's sensors. Its unrefueled range is approximately 6,000 nautical miles (9,600 kilometers). 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."

The B-2 has a crew of two pilots, a pilot in the left seat and mission commander in the right, compared to the B-1B's crew of four and the B-52's crew of five

B-2 is performed by Air Force contractor support and is managed at the Oklahoma City Air Logistics Center at Tinker AFB, Okla.

The success of the B-2 was proved in Operation Allied Force, where it was responsible for destroying 33 percent of all Serbian targets in the first eight weeks, by flying nonstop to Kosovo from its home base in Missouri and back. In support of Operation Enduring Freedom, the B-2 flew one of its longest missions to date from Whiteman to Afghanistan and back.

The prime contractor, responsible for overall system design and integration, is Northrop Grumman Integrated Systems Sector. Boeing Military Airplanes Co., Hughes Radar Systems Group, General Electric Aircraft Engine Group and Vought Aircraft Industries, Inc., are key members of the aircraft contractor team. Another major contractor, responsible for aircrew training devices (weapon system trainer and mission trainer) is Hughes Training Inc. (HTI) - Link Division, formerly known as CAE - Link Flight Simulation Corp. Northrop Grumman and its major subcontractor HTI, are responsible for developing and integrating all aircrew and maintenance training programs

How far away is anti-gravity technology? It may already be operating...

Towards the end of an otherwise routine article on aircraft propulsion in Air International in January 2000, reprinted at aeronautics, well-known and highly respected aviation writer Bill Gunston speculated that the American Northrop B-2 Spirit heavy bomber already uses some form of anti-gravity technology:
"I have numerous documents, all published openly in the United States, which purport to explain how the B-2 is even stranger - far, far stranger - than it appears. Most are articles published in commercial magazines, some are openly published US Patents, while a few are open USAF publications by Wright Aeronautical Laboratory and Air Force Systems Command's Astronautics Laboratory. They deal with such topics as electric-field propulsion, and electrogravitics (or anti-gravity), the transient alteration of not only thrust but also a body's weight. Sci-Fi has nothing on this stuff."

What really put the cat among the proverbial pigeons was a feature published in a March 1992 issue of Aviation Week & Space Technology, entitled "Black world engineers, scientists, encourage using highly classified technology for civil applications". For the first time in open literature, this article explained how the B-2's sharp leading edge is charged to "many millions of volts", while the corresponding negative charge is blown out in the jets from the four engines.
"Take-off thrust of the [B2 engine] F118- 100 at sea level is given as '19,000lb (84.5kN) class' by Northrop Grumman and as '17,300lb (77.0kN)' by the USAF. These are startlingly low figures for an aircraft whose take-off weight is said to be 336,5001b (152,635kg) and which was until recently said to weigh 376,0001b (170,550kg). Aircraft usually get heavier over the years, not 20 tones [sic] lighter. Even at the supposed reduced weight, the ratio of thrust to weight is a mere 0.2, an extraordinarily low value for a combat aircraft."

In other words, Gunston is implying that the B2 is seriously underpowered unless there is some means of reducing its mass or of increasing its lift beyond that provided by conventional aerodynamic means.
"Other writers have commented on the size of the B-2 wing and noted that its stealth depends on the huge black skin being made of RAM (radar-absorbent material). This, say the physicists, is 'a high-k, high-density dielectric ceramic, capable of generating an enormous electrogravitic lift force when charged'."
So is this why the B2s cost US$1 billion each?
Gunston's article is controversial, (an interesting discussion on it in the rec.aviation.military Internet newsgroup is archived at google under the title "B-2A and electrogravity") but there is a precedent for a radical, cost-is-no-object, highly classified US military aircraft using two major sets of new technologies, one secret and the other VERY secret.

The legendary Lockheed A12/SR71 "Blackbird" reconnaissance aircraft was increasingly declassified in the late 70s/early 80s, with major details released on the structural and propulsion technologies that enabled that incredible aircraft, one of the great masterpieces of aeronautical engineering, to cruise at Mach 3. What wasn't declassified until several years later, long after the F117 stealth fighter had been unveiled, was the fact that it was also a stealth design! While stealth took second place to speed, the fact was that stealth elements were a major factor in the airframe configuration, design of which dated back to the late 1950s, twenty years before stealth technology was even mentioned by the US government.
Another example is the even more legendary North American P-51 Mustang fighter of World War 2. For years its outstanding performance was explained by its "laminar flow" wing technology (also used in the B24 Liberator bomber).

Shortly before former senior manager and engineer at North American Aviation, Lee Atwood, died a few years ago he wrote articles for a couple of aircraft magazines (see, for example, airspacemag) giving the real explanation. Using a phenomenon known as the "Meredith Effect", the Mustang's characteristic under-fuselage duct for the engine's radiator was so shaped internally that the heat from the radiator converted it into, effectively, a low-temperature ramjet, thrust from which at high speeds offset most of the drag produced by the radiator in the first place! Not even the servicing crews knew that this was the true function of the duct design!
We know that the JSF/F35 will incorporate a high degree of stealth, like the B-2, with the degree of stealth apparently varying between inner and outer customers. However, stealth is relatively old-hat; the F117, the first stealth aircraft, turns up regularly at air shows, much of the US 70s and 80s stealth program has been declassified and the general principles, if not specific applications, of stealth technology are now well-known in the unclassified world. I can't see it being worth risking the fall of the UK or Australian