Traveling at speeds of Mach 5 or higher, future bombers could strike targets worldwide within hours.

Even before the U.S. Air Force finishes building its fleet of 21 B-2 Spirit stealth bombers, aircraft futurists are busy designing the nation’s next bomber deep inside a secure vault at Wright-Patterson Air Force Base in Ohio. The B-2 may rule the skies for now, but the bomber that makes it obsolete is already on the drawing board.

Northrop Grumman has unveiled its concept for a hypersonic waverider (left) that could reach speeds of Mach 5 and above. Their concept vehicle with supercruise capability is a delta-wing craft (middle). Design drawings for the nation’s next heavy bomber, designated the B-3 (right), are a closely guarded secret.

It typically takes decades to develop a new weapons system such as a bomber aircraft. That’s why the Air Combat Command, which oversees the U.S. long-range bomber force, initiated a Future Strike Aircraft study. The purpose of the FSA study is to have the nation’s three prime contractors for airframes — Boeing, Lockheed Martin, and Northrop Grumman — look out to the year 2030 and beyond, developing concepts for future stealth bombers that will meet the anticipated needs of the Air Force. These concepts will guide Congress in planning how to spend the nation’s defense dollars in the future.

Final reports from all three companies, including preliminary concept drawings, are due to Wright-Patterson’s Aeronautical Systems Center this month. But one of the competitors, Northrop Grumman, has already unveiled some of its ideas. Designers at the company are covering all bases by submitting concepts for three classes of future heavy bombers: subsonic, supersonic, and hypersonic. The ambitious hypersonic concept proposed by Northrop Grumman would launch weapons at tremendous speeds of Mach 5 and above, equivalent to about one mile per second at sea level.

Why such a high-speed design? Because of advances in anti-stealth technologies, the survivability of future strike aircraft may depend on speed and altitude. "We will be exploring vehicles that would operate in the high subsonic range and others in the supercruise and hypersonic ranges," says Charles Boccadoro, FSA program manager for Air Combat Systems, a research arm of Northrop Grumman based in El Segundo, California. An aircraft with supercruise capability can travel at supersonic speeds without an afterburner; hypersonic aircraft fly at speeds of Mach 5 to 10.

The Air Force currently relies on fleets of three bombers: the 45-year-old B-52 Stratofortress, the 15-year-old B-1B Lancer, and the newly minted B-2. The nation’s next heavy bomber will be designated the B-3, but the Pentagon has not yet decided on its shape or capabilities.

However, military insiders say it is likely that the next bomber to be deployed will be a subsonic flying-wing concept based on lessons learned from the B-2, which is built by Northrop. This future bomber will be even stealthier than the B-2, with a larger payload and longer range, and might have the capability to launch small, unpiloted "daughter" aircraft. Although Northrop has released drawings of its supersonic and hypersonic exercises in forward thinking, the aerospace company has not released any artwork of its subsonic concept — probably because that work is farther along in development, and thus already classified.

With the advent of a new subsonic bomber, the aging B-52 might finally be allowed to retire. Designed by Boeing in the early 1950s as a strategic nuclear bomber, the B-52 will probably still be flying well into this century unless a suitable replacement can be built. The bomber is older than most of the pilots who fly it, but still an important part of the Pentagon’s arsenal. "By the time a suitable replacement is operational, most likely the B-52 will be an 80-year-old bomber," says Boccadoro.

The replacement will have to be stealthy across a range of wavelengths — including radar, infrared, and visual. Flickering skins to confuse heat-seeking missiles, active camouflage to fool enemy eyes, and near-zero radar returns are all important specifications of any future bomber. Already, new Czech-made bi-static radar systems designed to spot stealth aircraft like the B-2 and the F-117 fighter pose a threat, and Iraq has reportedly tried to acquire these radar systems. Meanwhile, attempts by other countries to build their own stealth aircraft, such as Russia’s Project 1.45, have prompted the Pentagon to fund research into its own anti-stealth radar systems.

Not only will the B-52’s replacement have to be stealthy, but it will also need a comparable bomb load. The psychological effect that the B-52 has when it carpet-bombs an area is something that has not been lost on military planners. During the Gulf War, just the sight of a B-52 was enough to make Iraqi troops abandon their tanks in fear. "Designing an aircraft that will live up to the legacy of the B-52 is a daunting task," says Boccadoro.

While subsonic designs proposed as part of the Future Strike Aircraft study may be the first ones built, the study also considers supersonic and hypersonic designs. Northrop’s supersonic concept, which could replace the B-1B, is a delta-wing aircraft that is capable of reaching supercruise speeds, much like the F-22 Raptor.

The follow-on to the B-1B is foreseen as being primarily a nuclear weapons carrier, giving the Pentagon a fast but recallable nuclear delivery system that will serve as a strong deterrent to many countries that are the new nuclear club members, such as India, North Korea, and Pakistan.

A hypersonic bomber also appeals to military planners because it can be recalled, retargeted, and reused — which can’t be done with intercontinental ballistic missiles. According to Boccadoro, "the Air Force has always preferred a mixed force of bombers and ICBMs. A hypersonic bomber would give the Air Force a capability it does not have, a fast-reaction force based safely in the continental United States and able to strike anywhere with nuclear or conventional weapons. That would serve as a great deterrent."

Pentagon planners would like to have an operational hypersonic bomber in their inventory by 2037, but before this can happen, many technologies — including some that don’t even exist today — will have to be perfected. With no crystal ball to consult, military aircraft contractors and Pentagon think-tankers will have to make educated guesses about advances in materials, propulsion systems, and weapons that won’t exist for another 20 years. As with the SR-71 Blackbird of yesteryear, much of what makes up a hypersonic bomber will have to be invented. No off-the-shelf hardware or software will do.

Designing and building a hypersonic strike aircraft will be a monumental task but not an impossible one. Already the technology of hypersonic flight is advancing with NASA studies (see Coming Soon: Hyper-X).

The hypersonic bomber concept proposed by Northrop is an air-breathing design capable of Mach 5-plus speed. Such a high-speed bomber would enable the Air Force to strike any target anywhere in the world within hours instead of days. Expensive deployments of bombers, personnel, and materials to foreign bases would become a thing of the past.