Stratolaunch lands its mammoth airplane early after a flight take a look at that didn’t meet all of its targets

Stratolaunch says the sixth flight test of its super-sized Roc carrier airplane ended earlier than planned when the team ran into an unexpected issue.

“While completing Roc testing operations, we encountered a test result that made it clear we would not achieve all objectives for this flight,” the California-based company, which was created by Microsoft co-founder Paul Allen more than a decade ago, said in Twitter update. “We made the decision to land, review the data, and prepare for our next flight.”

Stratolaunch’s 385-foot-wide, twin-fuselage airplane is the world’s largest aircraft by wingspan. Stratolaunch has been testing Roc at Mojave Air and Space Port in preparation for using the plane as a flying launch pad for rocket-powered hypersonic test vehicles.

The company, which was acquired from Allen’s estate by a private equity firm in 2019, didn’t specify the nature of the test results that led to the decision to land. For what it’s worth, one of the flight’s key objectives was to expand the testing envelope for the center-wing pylon that will carry and release the hypersonic vehicles.

In a post-flight statement, Stratolaunch said that once members of the flight team encountered the unexpected test results, they focused on validating the aircraft’s general performance and handling characteristics with the addition of pylon hardware, and on validating landing gear operations.

Before takeoff, Stratolaunch said today’s flight test was projected to last as long as three and a half hours, but the actual flight time was one hour and 26 minutes. Roc reached an altitude of 15,000 feet, the company said.

Today’s test came a little more than a month after the fifth flight test, which was considered a success. Stratolaunch aims to begin testing its Talon-A hypersonic vehicles in flight later this year.

“Today’s flight builds on previous successful flights and hardware enhancements,” said Zachary Krevor, Stratolaunch’s CEO and president. “We will leverage this flight experience as we complete integrated testing in the coming months and prepare for Talon-A test flights.”

This report has been updated with details from Stratolaunch.