World's largest plane, Stratolaunch's Roc, aces 2nd captive-carry test flight

The world's largest airplane took to the skies again on Friday (Jan. 13), acing a record-breaking test flight.

Stratolaunch's Roc carrier plane, which has a wingspan longer than a football field, stayed aloft for six hours above California's Mojave Desert on Friday — longer than it ever has before. 

It was the ninth test flight for Roc overall and the second on which it hauled Stratolaunch's Talon-A hypersonic test vehicle aloft. Such "captive carry" tests are laying the groundwork for drop tests with the Talon-A, which the company aims to begin later this year.

"Our amazing team is continuing to make progress on our test timeline, and it is through their hard work that we grow closer than ever to safe separation and our first hypersonic flight tests," Stratolaunch CEO and President Zachary Krevor said in an emailed statement on Friday.

"The thorough evaluation of release conditions will provide data to reduce risks and ensure a clean and safe release of Talon-A during future tests," Krevor said. "We are excited for what’s ahead this year as we bring our hypersonic flight test service online for our customers and the nation."

Related: Stratolaunch test photos: The world's largest plane in action

Roc took off from the Mojave Air and Space Port in southeastern California on Friday morning and landed at the same site six hours later, at 5:51 p.m. EST (2251 GMT; 2:51 p.m. local California time). The plane attained a maximum altitude of 22,500 feet (6,860 meters), Stratolaunch representatives said.

In addition to being Roc's longest flight, Friday's outing marked the first time the plane has ventured outside the local Mojave area, the company added.

Microsoft co-founder Paul Allen established Stratolaunch in 2011. The initial aim was to launch rockets into space from mid-air, a strategy employed by Virgin Orbit with its LauncherOne rocket and Northrop Grumman with its Pegasus.

Allen died in 2018. A year later, Stratolaunch was purchased by Cerberus Capital Management and began shifting its focus; Roc, which sports a wingspan of 385 feet (117 m), is now a platform for air-launched hypersonic research and development.

If all goes according to plan, the company will offer customers efficient access to the hypersonic environment using Roc and its Talon series of robotic vehicles. Friday's flight — Roc's first since October 2022 — was a step toward making that happen.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.