Stratolaunch Systems, which is developing an extra-large airplane to launch small satellites into space, has begun engine testing on the aircraft, the company announced Sept. 19.

During the initial tests, the company started all six engines, first with auxiliary power, then with fuel. Made by Pratt & Whitney, a division of United Technologies Corp. (UTX), the PW4056 engines performed as expected, taking the “aircraft one step closer to providing convenient, reliable and routine access to low Earth orbit,” said Jean Floyd, Stratolaunch’s chief executive officer.

Concept of Stratolaunch's carrier aircraft. Photo: Stratolaunch.
Concept of Stratolaunch’s carrier aircraft. Photo: Stratolaunch.

Stratolaunch plans to test the engines at higher power levels and in varying configurations over the next few months. Taxi tests will follow.

Other recent ground tests for the aircraft have involved filling the six fuel tanks to ensure they work properly, and exercising the flight control system. In May, Stratolaunch rolled the aircraft out of its hangar in Mojave, Calif., for the first time (Defense Daily, May 31).

The plane, whose 385-foot wingspan is the longest ever built, is designed to send satellites into orbit using Orbital ATK [OA] Pegasus XL vehicles. Stratolaunch plans to conduct the first launch demonstration as early as 2019.

Air Force Secretary Heather Wilson toured the Stratolaunch hangar in July with Rep. Steve Knight (R-Calif.), whose congressional district is near Mojave. Wilson’s visit included “a conversation about the importance of innovation in space,” said Mike Martin, a spokesman for the secretary.