Stratolaunch's Roc aircraft during test flight in Mojave.

Stratolaunch's Roc aircraft during test flight in Mojave.

Stratolaunch, the aerospace company that built the world’s largest airplane, has added a former Pentagon official to its technical advisory group.

Mark Lewis joins the advisory group of the Mojave aerospace firm just weeks after it completed the critical design review for its Talon-A hypersonic test vehicles.

The Talon-A is a vehicle that is a rocket-propelled, autonomous, reusable testbed carrying customizable payloads at speeds above Mach 5. It is launched from the Roc carrier aircraft, the largest airplane in the world with a wingspan of 385 feet. Northrop Grumman Corp.’s subsidiary Scaled Composites built the craft at the Stratolaunch hangar in Mojave.

The technical advisory group is a specialized team that provides perspective and support for all aspects of the business, according to a release from Stratolaunch.

Lewis recently served as acting deputy undersecretary of defense for research and engineering at the Pentagon, a role that had him responsible for research, development and prototyping activities, Stratolaunch said in its release, adding that Lewis was the senior-most scientific professional in the Defense Department.

Lewis said he was excited to work with the other advisory board members on bringing a rhythm of test flight operations that the nation hasn’t seen since the end of the storied X-15 program.

“The Talon craft will be the reusable hypersonic ‘wind tunnel in the sky’ that many of us in the field have been talking about for years,” Lewis said in a statement.

Founded in 2011 by the late billionaire Paul Allen, the co-founder of Microsoft Corp., Stratolaunch was sold by Allen’s investment firm Vulcan Inc. about a year after Allen died in 2018. The new owner was identified in media reports as Cerberus Capital Management, a private equity firm specializing in distressed companies.