Hypersonic flight start-up Stratolaunch has achieved a “significant” milestone towards its goal of flying its in-development hypersonic aircraft for the first time before year-end.

Stratolaunch on 3 December completed a “captive carry” flight with a fully-fuelled example of its TalonA, an aircraft designed to fly at hypersonic speeds.

The test flight, which lasted 3h 22min, took place from Stratolaunch’s home base at Mojave Air & Space Port in the California high desert. The company calls the flight a “significant step” toward flying TalonA under its own power.

“Initial results from today’s flight show that the system has performed as predicted,” says Zahary Krevor, Stratolaunch chief executive. “We will determine our next steps pending the full data review of the test.”

Roc with TalonA TA-1 captive carry test

Source: Stratolaunch

Stratolaunch’s hypersonic system consists of the giant Roc mother ship jet and the rocket-powered TalonA flight hypersonic vehicle

The milestone comes just weeks after Stratolaunch completed taxi tests of the Roc aircraft carrying the fully fuelled TalonA.

“While we have conducted several successful ground tests fuelling and igniting the system, we needed to evaluate how the system performs in the flight environment prior to release,” notes Krevor.

Following the taxi test in November, a company official told FlightGlobal Stratolaunch hopes to achieve a powered flight of TalonA before the end of 2023. The company will attempt to hit the Mach 5 threshold for hypersonic flight during that event.

Stratolaunch’s hypersonic flight system incorporates two elements: a heavy-lift carry aircraft called “Roc” and the rocket-powered TalonA flight vehicle.

TalonA preflight Stratolaunch

Source: Stratolaunch

The rocket-powered TalonA will use liquid propellant to break the hypersonic barrier after being dropped from the Roc captive carry jet

TalonA is carried below Roc’s wing and between its twin fuselages. The rocket-propelled autonomous hypersonic aircraft are powered by Hadley engines, developed by Colorado-based manufacturer Ursa Major.

Roc is believed to be the largest aircraft currently flying, powered by six engines originally developed for the Boeing 747 commercial airframe. Stratolaunch says Roc boasts a payload of 226,800kg (500,000lb).

The TalonA airframe currently being tested – number TA-1 – is an expendable version for test purposes. Subsequent variants are to be reusable.

The company has three such craft either complete or under fabrication, with designations TA-2, TA-3 and TA-4.

In addition to private funding, Stratolaunch received a development contract from the US Air Force Research Laboratory and was selected as a subcontractor supporting the US Navy’s Multi-Service Advanced Capability Test Bed programme.