Stratolaunch conducted the first flight of its Talon powered vehicle on March 9, reaching “high supersonic” speeds in unmanned tests. According to flight tracking data, the Talon-A vehicle, designated TA-1, took off from the Mojave Air Spaceport in California on the company’s Roc aircraft at 10:17 ET. The aircraft was flying west toward a location in the Pacific Ocean off the coast of central California, where it released TA-1 at an unspecified time. Rock returned to Mojave four hours after takeoff.

Stratolaunch executives said in a call with journalists that they could not disclose the TA-1’s maximum speed or altitude during its flight, citing “private agreements” with unnamed customers. However, they were satisfied with the flight.

“As part of successfully achieving our test goals, we have achieved this high supersonic regime approaching hypersonic flight,” said Zachary Crevor, president and chief executive officer of Stratolaunch. Hypersonic flight is generally defined as speeds above Mach 5.

Aaron Kessebeer, senior vice president of design and operations, said the TA-1 achieved key test objectives, including release from the Roc and engine ignition, sustained acceleration and climbing at high supersonic speeds while maintaining control, then decelerating and gliding inward. Ocean Expendable vehicle TA-1 was not withdrawn.

“Overall, we are incredibly pleased with TA-1’s performance today,” he said. “At this point we are in a good position to continue with the test series we have planned.”

The company’s next vehicle, the TA-2, is the first reusable hypersonic vehicle. Flight tests are planned to begin in the second half of the year, and construction of another TA-3 reusable vehicle is underway. Stratolaunch is also modifying a Boeing 747 purchased last year from Virgin Orbit’s bankruptcy filing to serve as a second air launch platform.

Stratolaunch was founded more than a decade ago by Microsoft co-founder Paul Allen to provide air launch services using a giant six-engine twin-fuselage aircraft. The company has at various times reviewed SpaceX’s Falcon 9 variant, a vehicle concept from Orbital ATK (now part of Northrop Grumman) called Thunderbolt, and the company’s existing but much smaller Pegasus XL rocket. He then began work on his own launch vehicle and engine.

The company bounced back after Allen’s death in 2018. The company abandoned plans to build its own launch vehicle and was later sold to private equity firm Cerebus. The company announced in 2020 that it would instead focus on developing hypersonic vehicles to be air-launched by Roc.

TA-1’s flight was also an important milestone for Ursa Major Technologies, the company that developed the Hadley engine that powers the vehicle. Using liquid oxygen and kerosene, this engine was designed to produce 5,000 pounds of thrust. Ursa Major did not publish any flight tests of this engine prior to the TA-1 flight.

Hadley’s engine ran for about 200 seconds during the flight, Cassebeer said. “The Hadley engine performed very well today. It met all our expectations,” he said.