The Air Force is developing an upgrade to its long-range, high-altitude B-2 Spirit stealth bomber allowing it to better detect increasingly sophisticated enemy air defenses at longer ranges, service officials said.

Modern air defense systems are improving at a rapid pace as computer processing power grows exponentially. U.S. aviation leaders have grown concerned that these advancing air defenses will make stealth aircraft like the B-2 more vulnerable.

The B-2’s stealth technology, as it was configured and envisioned in the 1980s, did not fully anticipate or account for these advances that allow air defenses to detect aircraft through a wider range of frequencies and detect them at further ranges. Engineers have developed high-end air defense systems that are increasingly mobile and able to utilize digital, networked processing technology.

Russian-built S-400 air defense systems, for example, are one of many more modern systems which use three different missiles to target planes at ranges up to 250 miles.

As a result, some analysts and weapons developers have even raised the question as to whether today’s stealth technology is still relevant and effective.

With these questions in mind, the Air Force is working on substantial technical changes to the B-2’s Defensive Management System, or DMS – a technology that uses sensors, passive receivers and computers to alert air crews about the location of enemy air defense systems, among other things.

“We will get a much more capable system in seeing the threats as you penetrate adversary air space, giving the pilot the ability to re-route and avoid those areas,” said Eric Single, chief of the Global Strike division for Air Force acquisition.

Built by Northrop Grumman, the B-2 Spirit costs about $2.2 billion per aircraft. It can reach altitudes of 50,000-feet and carry 40,000-pounds of payload. First produced in 1989, the stealth bomber was engineered to deliver weapons behind enemy lines and evade Soviet air defenses.

If the B-2s stealth technology cannot avoid detection from high-end air defenses, its upgraded DMS technology can at least ensure the air crew knows where the threats are in real time in order to avoid flying into striking range, Single explained.

“It does not counter those threats (advanced enemy air defenses). What it does is identifies them and locates them so the pilots can avoid getting within those lethal ranges. When we mission plan a B-2 sortie, we use an auto-router which is a computer program which takes the threat information that we know and tries to design a route that maximizes the aircrafts stealth configuration and minimizes any exposure to threats that are out there,” Single said.

The B-2 does have the ability to use a data link known as Link 16 to communicate and receive mission updates while in flight, but the upgraded DMS will help the aircraft detect radar emissions from enemy air defenses. In particular, the new DMS technology will better enable crews to receive updated information about the locations of potential threats – while in flight.

“The advanced processors on the DMS modernization program will enable pilots to make adjustments on the fly in flight – as threat indications change,” Single said. “By the time you get to enemy territory it could be 10, 12, 15 hours since take off and a lot of threats change.”

The DMS upgrade, soon to be entering the Engineering Manufacturing and Development phase, is slated to be ready for service on B-2 aircraft by 2021.

“The DMS system keeps the B-2 viable as long as possible and enables you to penetrate into those high threat areas moving into the future. You don’t know what you don’t know until you get into enemy territory and those threat systems actually radiate you may or may not know where they are,” Single said.

Future Stealth Bomber

At the same time, increasingly sophisticated integrated air defense systems may force the Air Force to re-examine some of the roles and missions of the B-2 in coming years, Single explained.

“The B-2 is a very effective weapons system – it may be a little more challenged in next-generation threat environments. You may not necessary take that platform in every scenario but that does not mean you couldn’t still utilize the B-2 in moderate threat environments as opposed to those really high-end threat environments,” Single said.

Single made the point, however, that stealth technology was also evolving alongside modern air defenses – saying newer stealth configurations are informing development of the Air Forces new, next-generation Long Range Strike Bomber, or LRS-B, slated to fly alongside the B-2.

“As enemy threat systems continue to advance, the B-2 will be more and more challenged when it comes to penetrating those highly defended areas. One of the main reasons we have for the next bomber program coming on line – to address that next level of stealth technology,” he said. “A lot of work will need to be done to figure out the addition of the new bomber when that fields in the mid-2020s in terms of how that changes the calculus.”

The Air Force’s LRS-B is slated to be ready sometime in the mid-2020s.

The DMS upgrades are part of a sweeping modernization overhaul of the nuclear bomber designed to keep it flying and relevant through 2058.

Regarding the future efficacy of emerging stealth technologies, Single made the point that stealth or low-observable configurations are merely one aspect of a broader equation which includes speed, altitude, electronic jamming and deception – among other things.

“There are many pieces of avoiding detection and defeating an enemy IAD (integrated air defense),” Single said.

-- Kris Osborn can be reached at Kris.Osborn@military.com