Stratolaunch’s Roc aircraft returned to the skies on October 2, completing two flights from Mojave Air & Space Port in California on the same day after approximately five months without flying.
The unusual twin-fuselage aircraft, registered N351SL, has a wingspan of 385 feet (117 meters), the largest of any aircraft ever built. Rather than a conventional transport aircraft, Roc was designed as an airborne launch platform for large test vehicles and other payloads.
AirNav Radar data show that Roc departed Mojave at 8:54 a.m. PDT and returned at 9:34 a.m. after a 39-minute flight. It took off again at 11:27 a.m. and landed at 12:02 p.m., completing a second 35-minute sortie.
Neither flight involved an external payload. Stratolaunch said the sorties were conducted for pilot training and proficiency, supporting the crews required for the company’s hypersonic flight-test operations.
Return after five months
Roc had last flown on May 2, when it completed a three-hour and 39-minute flight from Mojave. The October operations ended a five-month absence and became the aircraft’s fifth and sixth flights of 2026.
The aircraft had previously flown once on January 20 and twice on April 19. The October sorties were considerably shorter than the May mission and remained close to Mojave, with the second flight consisting of several circuits in the vicinity of the airport.
Powered by six Pratt & Whitney PW4056 engines, Roc was originally developed to carry rockets beneath the center section connecting its two fuselages. Stratolaunch later redirected the aircraft toward its hypersonic testing business.
The aircraft has since been used to carry and release the company’s Talon-A vehicles. These reusable autonomous vehicles provide a platform for testing technologies at hypersonic speeds.
Growing launch aircraft fleet
Stratolaunch has expanded its airborne launch capability beyond the purpose-built Roc. The company acquired a former Virgin Orbit Boeing 747-400, now named Spirit of Mojave, and modified it to carry Talon vehicles.
The 747 provides a more conventional and deployable platform that can operate from a wider range of airports than Roc, giving Stratolaunch additional flexibility for hypersonic test campaigns.
The company is also preparing another large aircraft for the same role. In September, Stratolaunch announced the acquisition of a Boeing 777-200ER that will be converted into an additional airborne launch platform.
The 777 is expected to enter service in 2027. Stratolaunch estimates that the aircraft will increase its flight-test capacity by approximately 35% as demand for hypersonic testing grows.
