After a successful launch of its Falcon 9 rocket, SpaceX has ran into a thruster issue with its Dragon cargo-carrying capsule as it orbits the Earth in a mission to resupply the International Space Station for NASA.
The Dragon spacecraft has four thruster pods, which work to control the spacecraft as it makes its way to the space station. Following the 7:10 a.m. PST blastoff, only one of the thrusters was working.
In an afternoon conference call, SpaceX Chief Executive Elon Musk said that a second pod was functioning and that he expected the two others to come online later.
“I’m optimistic that we’ll be able to turn all four thruster pods on and restore full control,” he said.
Musk speculated that the anomaly could be traced back to a stuck valve or other blockage that caused a drop in pressure in the oxidizer tanks of the pods. But he cautioned that it was too soon to determine the root cause.
"I think it was essentially a glitch of some kind and not a serious thing," Musk said, adding that Dragon had deployed its solar arrays, which helped it stabilize and generate power.
The capsule is packed with more than 1,200 pounds of food, scientific experiments and other cargo for the six astronauts aboard the space station. The mission plan was that Dragon would reach and attach to the space station Saturday, but NASA officials now say it's unclear when that will occur.
The space agency requires at least three thrusters be functioning for the capsule to approach the space station. If those thrusters do come online, NASA will review the data before giving the go-ahead for docking.
William Gerstenmaier, NASA’s associate administrator for Human Exploration and Operations, said during the conference that the agency would “make sure it doesn’t put the station in danger.”
The problem arose after the spacecraft separated from the rocket’s upper stage.
John Insprucker, Falcon 9 product director, told viewers during SpaceX’s live webcast: "It appears that although it reached Earth orbit, Dragon is experiencing some type of problem right now. We'll have to learn the nature of what happened."
The live webcast was then shut down.
SpaceX, formally named Space Exploration Technologies Corp., has already performed successful NASA resupply missions to the space station. There was one official mission in October, and a demonstration mission took place in May.
Both of those missions also had problems.
In May, a problem with the Dragon's onboard sensors pushed back its capture by the station to about two hours later than planned.
In October, one of the nine engines on the massive Falcon 9 rocket experienced a problem and shut down shortly after launch. Because of the glitch, a satellite the rocket was carrying didn't reach proper orbit, but the NASA resupply mission went on as planned and the Dragon capsule connected with the space station.
SpaceX is the only commercial company to resupply the space station. The company has secured a $1.6-billion contract to carry out 12 cargo missions. If the current mission is successful, it would be the second.