Stratolaunch has completed its fourth flight test of the carrier aircraft, known as Roc.

Roc is the world's largest aircraft, with a 385ft wingspan. The aircraft flew for one hour, 43 minutes over the Mojave Desert and reached an altitude of 15,000 feet (4,57 m). As part of this latest flight, pilots further prepared the carrier aircraft to support launches of its upcoming hypersonic testbed vehicle, Talon-A.

Launched from the Roc carrier aircraft, Talon-A vehicles are rocket-powered, autonomous, reusable testbeds carrying customisable payloads at speeds above Mach 5. This capability enables routine access to the hypersonic flight environment, which is critical for scientific research, technological development, and component demonstration.

Initial results from the test objectives included: continued evaluation of the aircraft's performance and handling characteristics; and validation of full landing gear operations including door functionality and alternate gear extension.

"Today's successful flight demonstrates and validates improvements to the carrier aircraft's systems and overall flight performance," says Dr. Zachary Krevor, Stratolaunch president and chief operating officer. "The full landing gear retraction and extension brings the carrier aircraft closer to operational status, a milestone that is necessary to ready the aircraft for Talon-A separation and hypersonic flight tests later this year."

In addition to testing the carrier aircraft, the team continues to make progress on system integration of two Talon-A test vehicles, TA-0 and TA-1. The team has also started fabrication of a third vehicle, TA-2, the first fully reusable hypersonic test vehicle. The company anticipates beginning hypersonic flight testing in 2022 and delivering services to government and commercial customers in 2023.