SpaceX’s Dragon cargo spacecraft experienced a thruster issue after lifting off March 1 and achieved initial orbit on NASA’s second Commercial Resupply Services mission to the International Space Station (ISS).

SpaceX CEO and chief designer Elon Musk said his Hawthorne, Calif.-based control team would hold off on deploying the Dragon’s solar arrays until it can resolve an unspecified issue that inhibited three of four thruster pods from initializing. The power-generating solar arrays were scheduled for deployment 11 min. after the 10:10 a.m. EST liftoff from Cape Canaveral.

“Holding on solar array deployment until at least two thruster pods are active,” Musk reported by Twitter. SpaceX was to make the attempt at deployment as the capsule flew over an Australian ground station. A SpaceX spokeswoman says that once at least two pads are active, controllers will initiate a series of burns to reach the ISS.

The effect of the difficulties on Dragon’s scheduled rendezvous with the six-person space station early March 2 is unclear, according to spokesman in NASA’s Mission Control Center.

Station astronauts Kevin Ford and Tom Marshburn have been preparing to position themselves in the ISS’s U.S. segment Cupola observation deck, ready to reach out with the 58-ft.-long Canadian robot arm to grapple the supply vessel at 6:30 a.m. EST.

Berthing operations of the capsule, filled with slightly less than 2,300 lb. of U.S., European and Japanese research equipment and other internal and external supplies, had been scheduled to begin at 8:40 a.m. EST March 2. Dragon would be berthed to the U.S. segment Harmony module for internal access by the crew on March 3. 

The two-stage Falcon 9/Dragon stack lifted off as scheduled. Climbing on a northeasterly course, the Falcon 9 rocket placed the Dragon supply ship in its initial orbit of 124 X 202 mi. (199 X 323 km). Maneuvers are planned to propel the Dragon toward the 250-mi.-high space station. NASA and SpaceX flight control teams, working from NASA’s Johnson Space Center in Houston, and SpaceX facilities in Hawthorne, Calif., plan to consult during the final stages of rendezvous for a series of  four “go/no-go” decisions that permit the unpiloted vessel to maneuver close enough to the orbiting science laboratory for the robot arm grapple.

The mission is the second by SpaceX under a $1.6 billion NASA cargo services contract awarded in late 2008. The first, launched in October, followed a six-year, NASA-led Commercial Orbital Transportation Services partnership.

Dragon is scheduled to remain berthed to the station until March 25. Once unberthed using the Canadian robot arm, the capsule will aim for a parachute descent into the Pacific Ocean off Baja, California. SpaceX recovery vessels will be on station and are expected to retrieve the capsule and its return cargo of just under 2,700 lb. of research equipment and hardware in need of refurbishment.