The failure of deterrence in the air is not due to the advanced nature of a bomber; it is due to the lack of enough bombers to be there, available and maintainable, across the missions they are likely to have. The B-21 Raider of the U.S. Air Force is designed to replace the old B-2s and B-1Bs, as well as the main workhorse of a modern bomber fleet along with modernized B-52s. Radar signature and range are never the only promises of the aircraft. It is also associated with the speed with which the platform can absorb new sensors, software, and weapons using an open system approach as well as the widespread nature of its deployment without the special facilities that limited previous stealth fleets. It is exactly that flexibility that leads to the same discussion being repeated over and over again, the simple question of whether a force planned with 100 aircrafts, can bear the burden of the global tasking, training pipelines, maintenance cycles, and surge needs simultaneously.
Within the bomber community, the figure is becoming more of a starting point, rather than an endpoint. The fact of concurrent strategic demand is one of the pushing forces. One of these analyses suggests that, in the first instance, the United States has to deal with two large nuclear rivals whose armies are modernising, and their air defence has become more dense and more networked. One of the limited number of tools that can be positioned, signaled, and held back in a manner that conveys both ability as well as restraint is a penetrating bomber, yet has the capability to conduct conventional operations on a large scale. The B-21 is capable of doing so with conventional or nuclear payloads, but the fleet size dictates the presence of either of those at a given time at a location other than one.
The pressure is not an imaginary one. Gen. The commander of Air Force Global Strike Command at the time, Thomas A. Bussiere, informed legislators that the total bomber force of 220 would most probably be required to meet the demand; by 75 B-52Js upgraded, that meant a minimum of 145 B-21s. Other powerful estimations are higher. The Center of Strategic and Budgetary Assessments has proposed 288 B-21s to be able to sustain a force capable of meeting two major-power requirements. Mark Gunzinger of the Mitchell Institute has repeatedly pointed out a fleet of 225 or so Raiders as a viable point at which to operate on a sustained, high-end basis with large target sets way out in the back of sophisticated defenses.
There is a more hidden variable under those figures: readiness economics. The increased capacity of a larger fleet is not the only result; it may also decrease the per-aircraft maintenance load since fixed training, depot and basing overheads are distributed among more tails. Such a dynamic is important to a stealth bomber that will be continuously modernized and relevant decades.
The B-21 is also being drawn into a bigger system by operational planning. Through an infrequent on-the-record briefing of the program direction, AFGSC commander Gen. Stephen L. Davis called the B-21 as “a benchmark of acquisition” and said that digital engineering was the key to making the program stay on schedule. He also cited that the Raider will be “more connected than the B-2”, and cited a scenario in which under some conditions, the Raider would be companionate with the F-47 6th-generation fighter of the Air Force, further supporting that survivable penetration was increasingly being an issue of teams, rather than one of platforms.
Still the “problem of numbers” is hard to get rid of. Bombers are put under a lot of training and undergoing upgrades, maintenance, and inspections; only a small percentage can be tasked immediately. That fraction is extended by geography. A fleet calculated large on paper can easily be reduced to thin once the calculation of dispersal, basing resiliency and continuous presence are put in the equation.
The engineering proposal of the B-21 is that it will be flexible, survivable, and maintainable compared to the previous stealth bombers. The strategic case is easier: believable choices need sufficient aircraft to exist in more than just one place, more than just one task, and more than a temporary burst.
