Last year, SOFREP reported on Lockheed Martin’s plans to develop a hypersonic successor to the legendary SR-71 Blackbird, a military reconnaissance aircraft that retains the title of fastest winged craft ever to take to the skies despite having been retired for nearly two decades. Now, Boeing has announced that Lockheed isn’t the only company with its sights set on developing a worthy successor to the Blackbird using the same scramjet technology.

This week, Boeing unveiled a design concept for a hypersonic aircraft they feel could compete with Lockheed’s developmental aircraft. The model, which has not yet been approved for full-scale development, shows what Boeing’s hypersonic demonstrator could look like if brought to fruition, and according to the aerospace company, the plane would be capable of speeds in excess of Mach 5.

The famed SR-71 was rumored to be able to exceed Mach 3. Lockheed Martin originally claimed their SR-72 would be able to reach speeds as high as Mach 6, but have since tempered those claims back down to Mach 5 as well. While Lockheed is rumored to already have a demonstrator under development, Boeing is only now working out exactly how they intend to field their own.

Artist’s rendering of the Lockheed Martin demonstrator. (Lockheed Martin)

“We asked, ‘What is the most affordable way to do a reusable hypersonic demonstrator vehicle?’ And we did our own independent research looking at this question,” said Kevin Bowcutt, Boeing chief scientist for hypersonics.

His plan is to first build a single engine proof of concept aircraft that is around the size of an F-16. Then, following the success of that aircraft, a second prototype, with two engines that is roughly the size of the original SR-71 will be produced for further testing.

Although Boeing may be behind the competition in terms of developing a Blackbird replacement, they’re no strangers to hypersonic aircraft. In May of 2013, Boeing set a record for sustained air-breathing hypersonic flight with their experimental unmanned X-51, which maintained a speed of Mach 5.1 for three and a half minutes before expending all of its fuel and crashing into the Pacific Ocean.

Of course, the methods used to set that record couldn’t carry over into an SR-72 for actual use. The X-51 was carried into the air and dropped by a B-52, then used rocket engines that brought it up to Mach 4.8 before jettisoning the booster and engaging its scramjet to carry it across the Mach 5 barrier. Whatever the SR-72’s capabilities are when complete, it can be expected that it will need to be able to take off under its own power and will not be able to rely on single use rocket stages for acceleration.

Lockheed Martin is currently Boeing’s biggest competitor in terms of building an advanced aircraft that is capable of achieving hypersonic speeds, but even Lockheed’s demonstrator isn’t expected to take to the skies until sometime in the 2020s. It seems possible that by then these aircraft may be expected to take on more than just reconnaissance roles in America’s national defense. In the Blackbird’s days, satellites were not nearly as capable of providing up to the minute intelligence as they are today, and America’s nuclear bomber fleet is aging rapidly. It seems possible, even likely, then that a future SR-72 or variant hypersonic aircraft may have to become a nuclear capable asset, as our bombers become increasingly incapable of managing advanced anti-aircraft systems employed by peer and near-peer level opponents.