The commercial SpaceX rocket venture launched its unmanned Dragon capsule on a cargo run to the International Space Station on Friday, and then spent hours addressing a gnarly problem with the Dragon's thruster system. The problem was solved, but not before it forced at least a day's delay in the cargo craft's space station rendezvous.
SpaceX's Falcon 9 rocket made a problem-free ascent from its launch pad at Cape Canaveral Air Force Station in Florida at 10:10 a.m. ET to send the Dragon into space. But a half-hour after launch, SpaceX founder Elon Musk said in a Twitter update that controllers encountered an issue involving the capsule's thrusters.
"Issue with Dragon thruster pods, " Musk wrote. "System inhibiting three of four [pods] from initializing. About to command inhibit override."
Each pod contains a grouping of thrusters that are used to guide the Dragon's course in orbit. In an email, SpaceX spokeswoman Christina Ra said the Dragon "experienced an issue with a propellant valve" after it achieved orbit. "One thruster pod is running, " she said. "We are trying to bring up the remaining three. We did go ahead and get the solar arrays deployed. Once we get at least two pods running, we will begin a series of burns to get to station."
SpaceX's controllers wrestled with the problem for hours. Just before 3 p.m. ET, Musk said that a second thruster pod was up and running. After another hour, he reported that the other two pods were working as well. "Thruster pods one through four are now operating nominally. Preparing to raise orbit. All systems green, " Musk said on Twitter. And an hour after that, he sent another tweet saying that the orbit-raising burn was successful. "Dragon back on track, " he wrote.
During a teleconference with reporters, Musk speculated that there was a stuck valve or "potentially some blockage" in the lines for pressurizing the thrusters' oxidizer tank. Cycling the valves and releasing a blast of pressurized helium cleared the lines, he said. There was no indication that the blockage did any damage to the system, although SpaceX and NASA were taking a closer look at the cause of the problem and its aftermath.
Musk voiced relief that operations were getting back to normal. "It was a little frightening there, " the 41-year-old billionaire coolly acknowledged.
The SpaceX Falcon 9 rocket lifts off from Cape Canaveral Air Force Station in Florida, sending the Dragon capsule on a resupply mission to the International Space Station.
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