Stratolaunch Systems has opened a new hangar at the Mojave Air and Space Port in California that will be used to accommodate construction of the twin-boom carrier aircraft the Huntsville, Ala.-based startup is building to carry aloft a multi-stage satellite booster.

Gary Wentz, president and chief executive officer of the Paul Allen-backed company, said in a March 27 statement that completion of the 9,500-square-meter hangar keeps Stratolaunch on track to “hit our first test flight in 2016.”

Stratolaunch opened a smaller hangar in October that partner Scaled Composites is currently using to manufacture the aircraft’s wing and fuselage section. Billed as the “largest aircraft ever constructed,” the Stratolaunch carrier aircraft will use six 747 engines, weigh more than 500,000 kilograms and have a wingspan of more than 115 meters.

Stratolaunch tapped Dulles, Va.-based Orbital Sciences Corp. last year to replace Space Exploration Technologies Corp. as the company’s booster partner.

Orbital Sciences operates the air-launched Pegasus XL and ground-launched Taurus solid-fueled rockets and is preparing to debut the liquid-fueled Antares rocket in a test launch scheduled for April 17-19 from Wallops Island, Va.

Stratolaunch has not said whether it will use a predominately solid- or liquid-fueled booster.

“Stratolaunch will employ a multi-stage booster to ensure … we can deliver payloads to multiple orbits,” Stratolaunch says on its website. “Orbital Sciences currently is studying alternative booster solutions to help us achieve that objective. Check back for future design updates.”