Members of the media gather around the SLS five-segment Solid Rocket Motor before it undergoes a static test fire at the Orbital ATK facility in Promontory, Utah March 11, 2015. The beefed-up space shuttle solid rocket motor passed a two-minute test firing in Utah on Wednesday, a key milestone toward the debut flight of NASA's deep-space launcher in 2018, the US space agency said. [Photo/Agencies]

The test was the first of two planned before two boosters are paired with four liquid-fueled modified shuttle main engines and topped with an Orion capsule for an unmanned debut run around the moon in 2018. Orion, flying on top of a United Launch Alliance Delta 4 rocket, made its initial test flight in December.

United Launch Alliance is a partnership of Lockheed Martin and Boeing.

NASA is spending about $3 billion a year to develop the Space Launch System rocket and Orion capsule, which are designed to fly astronauts to asteroids, the moon, Mars and other destinations beyond the International Space Station's 260-mile (418 km) -high orbit.

Orbital ATK, a newly formed merger of Orbital Sciences and Alliant Techsystems' Aerospace and Defense Groups, has a second NASA contract to fly cargo to the station, a $100 billion project of 15 nations. The company is revamping its Antares rocket after a launch accident in October.