Secret and slow could be watchwords for the U.S. Air Force’s new bomber program. Although major spending is getting under way, the service does not expect to see the aircraft in service before the mid-2020s—a longer timescale than the “2018 bomber” discussed in 2008. In addition, Maj. Gen. Dave Scott, USAF director of operations capability requirements, confirmed in February that the aircraft will be “highly classified—we are not going to talk about any of its attributes.” Beyond stating that the aircraft will be optionally piloted and nuclear-capable, the Pentagon has said little.

The magic numbers for the bomber are a fleet size of 80-100 and a flyaway cost of $500 million, both numbers set by Defense Secretary Robert Gates. “The secretary doesn’t want another B-2,” one Air Force leader remarked recently.

The extended schedule reduces risk and avoids overlap in funding with the delayed Joint Strike Fighter (JSF). Reports suggest that funding will average under $1 billion a year through fiscal 2016, when JSF funding should tail off.

One key capability is almost certainly under development: the combination of extreme low-observable (ELO) technology and unprecedented aerodynamic efficiency. This will not only appear on the bomber but on one of two critical “enablers” for the long-range-strike family of systems: unmanned aerial vehicles (UAV) designed for stand-in airborne electronic attack (AEA), and for penetrating, persistent intelligence, surveillance and reconnaissance (ISR). Both were identified by Scott in a briefing last October.

Stand-in AEA, with jamming effects delivered by an ELO platform, is an important adjunct to stealth. Although networked radar systems are improving their ability to detect stealthy targets in the Lockheed Martin F-22/F-35 class, moderate-power jamming is likely to degrade that capability. It is also expected to defeat efforts to detect ELO targets in the foreseeable future. Lockheed Martin’s RQ-170 Sentinel UAV could be the interim solution to this requirement.

Penetrating ISR demands a combination of endurance and ELO, and such a system is probably the goal of the large special access program (SAP) awarded in 2007-08 to Northrop Grumman. One key technology, the subject of a good deal of open-source work, is the ability to sustain laminar airflow on a swept wing: this technology alone could deliver 32 hr. of time-on-station in an all-wing UAV, according to a Northrop Grumman technical report.

If such a SAP produces results, in terms of the vehicle and its primary sensors (synthetic aperture radar with ground-moving target indication), it would explain why USAF has been willing to curtail the Global Hawk Block 40 program.

Penetrating, persistent ISR is vital for the long-range strike family of systems because it provides targeting for other weapons: a Conventional Prompt Global Strike missile, new subsonic cruise missile launched from aircraft or submarines, or a hypersonic missile. In turn, that capability allows USAF to focus the new bomber requirement more narrowly and avoid mission and cost creep that apparently affected the earlier Next Generation Bomber (NGB).

For example, the new bomber could be smaller than the NGB was envisioned to be, because it could also provide targeting for offboard weapons, with less need for a “deep magazine” of onboard weapons. Offboard sensors would also reduce demand for simultaneous long range and high resolution for onboard sensors, reducing aperture size. Overall, the new bomber may emerge smaller than medium bombers of the past, and well under half the size of the B-2.

The Air Force is also leaning toward the adoption of features developed in Advent (Adaptive Versatile Engine Technology) and Heete (Highly Efficient Embedded Turbofan Engine) in the new bomber. Heete is aimed at cruise efficiency and delivering electrical power, necessary to support directed-energy weapons, and is expected to yield a fuel-burn improvement of 35% over current low observable-compatible subsonic engines.

One factor will drive up the cost of the bomber’s R&D: its status as a SAP. SAP status—whether the program is an acknowledged SAP, as the bomber is likely to be, or completely black—incurs large costs. All personnel have to be vetted before they are read into the program. Information within the program is compartmentalized, reducing efficiency. SAP status has been estimated to add 20% to a program’s cost.

The most likely reason for this measure is the sensitivity of ELO technology, combined with the fact that the U.S. is the target of what may be the most extensive and successful espionage program in history—China’s Advanced Persistent Threat.