Stratolaunch completes first engine test

Stratolaunch, the world’s largest all-composite aircraft, designed to carry payloads into Earth orbit, has begun testing of its six Pratt & Whitney engines.

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Stratolaunch (Seattle, WA, US) announced on Sept. 19 that it has completed the first phase of engine testing on its massive, composites-intensive aircraft, designed to deliver payloads into Earth orbit. The Stratolaunch is powered by six Pratt & Whitney turbofan engines.

Engine testing was conducted with a build-up approach and consisted of three phases. First as a ‘dry motor,’ where the company used an auxiliary power unit to charge the engine. Next, as a ‘wet motor,’ where fuel was introduced. Finally, each engine was started one at a time and allowed to idle. In these initial tests, each of the six engines operated as expected.

The team completed testing of all six fuel tanks to ensure proper operations. Each of the six fuel tanks were filled independently to ensure proper operation of fuel mechanisms and to validate the tanks were properly sealed.

In addition to fuel testing, the company began testing the flight control system. Stratolaunch exercised the full limits of motion and rate of deflection of control surfaces on the wing and stabilizers. Building up to this week’s engine tests, prerequisite testing of the electrical, pneumatic, and fire detection systems were completed successfully.

The company will continue to test the aircraft’s engines at higher power levels and varying configurations, culminating in the start of taxi tests.

Stratolaunch is the world’s largest aircraft by wingspan and is the largest all-composite plane ever built. With a payload capacity of more than 500,000 lb and an operational range of approximately 2,000 nautical miles, Stratolaunch is capable of delivering payloads to multiple orbits and inclinations in a single mission.

Stratolaunch’s reusability and air-launch capabilities enable it to take an airport-style approach to operations for launch services. Stratolaunch will take off from a runway, rather than a logistically vulnerable fixed range, which allows it to avoid hazards such as inclement weather, airborne traffic and heavy marine activity. Stratolaunch was produced at the Mojave Air & Space Port in Mojave, CA, US, and should be operational by the end of this decade.