The B-1B ‘Bone’ Rolls Out Of The World’s Largest Anechoic Test Chamber

Twenty-five years ago, the a B-1B rolled into the then-brand-new Benefield Anechoic Facility (BAF) at Edwards AFB, which remains the largest anechoic chamber in the world. This marked the first defensive systems test for the BAF. Now, two and a half decades later, the B-1B headed back into the sci-fi-like facility for another round of tests on its notoriously complicated ALQ-161 Threat Protection System.

Rodney Brooks, of the 579th Software Maintenance Squadron describes this system like this:

“The ALQ-161 receives all of the radio frequency energy when it’s flying and will process it and determine if it’s a threat, and then it can set up automatic jamming to jam that RF (radio frequency) energy from a missile, aircraft or ground missile.” 

The system has long been a reliability headache for the USAF, but upgrades have made it more stable and effective in recent years. Stuffing a full-on B-1B into the BAF allows engineers to collect data on the system under extremely tight laboratory conditions so that it can be further improved.

Now, in an age of sensor fusion and highly capable and widely proliferated integrated air defense systems, the B-1B needs the BAF more than ever, as its self-protection suite has to keep the jet alive in medium- and higher-threat environments. This is why successfully integrating new technologies and software into the suite is so critical. Some of these past upgrades have included towed decoys that are doghoused in the B-1B’s empennage, and enhanced digital signal processing.

B-1B sits inside the cavernous BAF for electronic warfare system testing. , USAF

The BAF was actually designed during the Reagan era, primarily to support the B-1 and its faltering electronic self-defense suite. Since then, it has serviced aircraft from around the globe. The facility is even named after Rockwell chief test pilot Tommie “Doug” Benefield, who perished on August 29th, 1984, in a crash of a B-1A—the faster Carter-era progenitor of the B-1B.

The DoD has many unique and elaborate soundstage-like testing facilities. Some develop missile seekers, others test airplanes and other equipment under extreme temperatures. Even Edwards AFB’s BAF is just one of multiple anechoic chambers available for military testing, although its massive size, able to accommodate any aircraft in the Pentagon’s inventory, makes it unique. The other-worldly interior of the BAF is described by the USAF:

“The chamber is filled with polyurethane and polyethylene pyramids, radar absorbing material designed to stop reflections of electromagnetic waves. The size of the pyramids, which are painted dark blue or black, varies depending on the particular frequency and test procedure being conducted. Aircraft systems can be tested and verified that they work properly prior to actual flight test.” 

B-1 sits inside the BAF during testing, decades ago., USAF

A big part of the tests that BAF and other anechoic chambers do regards how the aircraft’s electronic systems and emissions interact with one another, and with those from the outside world. For aircraft with advanced electronic warfare suites, like the B-1B or the EA-18G, getting the aircraft to not jam itself can be a major undertaking. 

B-1B rolls out of the BAF after two weeks of intensive testing. , USAF

After two weeks of testing, the “Bone” rolled out of the chamber this morning, and Edwards AFB posted this little gem showing the B-1B doing nap-of-the-earth flying over the Mojave Desert. It sure looks happy to be out of that dark and scary hangar!

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