Hawthorne rocket company SpaceX ran into trouble on its third mission to the International Space Station after what seemed like a picture-perfect launch Friday morning from Cape Canaveral in Florida.
SpaceX's Falcon 9 rocket lifted off on schedule at 7:10 a.m. California time, and released the Dragon space capsule into orbit nine minutes later. However, a possible blockage in a propellant valve prevented three of Dragon's four thruster pods from working.
Now the earliest Dragon can rendezvous with the space station is Sunday, said Michael Suffredini, NASA's International Space Station program manager, in a conference call with reporters.
"If we can convince ourselves that the data is good, I suspect we can find an opportunity on Sunday," Suffredini said, referring to the data NASA and SpaceX have been receiving about Dragon's thrusters and other operations.
Dragon was originally scheduled to arrive at the space station on Saturday.
However, SpaceX founder and Chief Technology Office Elon Musk seemed to hedge on the timing of a rendezvous.
Asked by a reporter if a weekend berthing was unlikely, Musk, who was on the same conference call, said, "That's probably the case."
"We're definitely not going to rush it and we want to make sure first and foremost that things are safe before proceeding," Musk said.
Musk, a wealthy entrepreneur who made his fortune as co-founder of PayPal, said Dragon is theoretically able to stay in orbit for "a few months," because its solar arrays were recharging the capsule's battery.
He added: "We could keep it up there for at least a month, at least trying to sort out any issues and get everybody comfortable with an approach to the space station. So it's going to be up there for a while."
By Friday afternoon, SpaceX was able to bring a second thruster pod into operation. Musk said the pressure was "nominal" - or normal - in the fuel lines of all four thruster pods, and that will allow SpaceX to enable the remaining two thruster pods.
"I'm optimistic we will be able to bring all four of them up and we'll work with NASA to see what's the next step in rendezvousing with the space station," Musk said.
Later in the day, Musk posted an encouraging tweet: "Thruster pods one through four are now operating nominally. Preparing to raise orbit. All systems green."
He followed that by tweeting: "Orbit raising burn successful. Dragon back on track.
NASA requires that Dragon have at least three of its four thruster pods working before it tries to approach the space station, said Suffredini, who noted that "it's not our intention to wave safety requirements."
Musk emphasized that the Falcon 9 rocket that carried Dragon into orbit "performed its job super well. It did absolutely nothing wrong."
Once Dragon was in orbit, SpaceX Mission Control in Hawthorne realized that three of the four thruster pods were not functioning.
Musk said a preliminary analysis showed that the problem may have been caused by a blockage in a tube that sends oxygen to fuel the thrusters.
Mission Control operators tried to clear the suspected blockage by "essentially pressure-hammering the valves," Musk explained. "That looks like it was effective."
Musk said he was not aware of any fluid or gas leakage or debris involved in the problem.
If the mission is a failure, SpaceX will receive only partial payment from NASA, Musk said, although he was not sure of the exact amount.
A mission failure for Dragon would not put the space station astronauts at risk of running out of food, water or clothing, NASA's Suffredini said. At worst, it would mean that some NASA research would have to be repeated. The space station has enough science experiments to last it probably to September.
Dragon is carrying 1,200 pounds of supplies, including food, air purifiers and materials to support 160 experiments.
Once NASA determines that it is safe for Dragon to approach the space station, it could take the capsule less than a day to conduct a series of burns for a rendezvous.
An astronaut on board the space station will use a robotic arm to grasp the space capsule and berth it to the giant lab complex.
Dragon is scheduled to remain on the space station for more than three weeks, and then return to Earth with 2,300 pounds of cargo, including crew supplies, scientific materials and space station hardware.
About six hours after Dragon leaves the station, the capsule will "de-orbit" and splash down in the Pacific about 250 miles off the Southern California coast.
This is SpaceX's third mission to resupply the space station, and the second under a $1.6 billion NASA contract that calls for at least a dozen such trips. The company officially known as Space Exploration Technologies Corp. sent a Dragon capsule to the orbiting lab in October. A demonstration mission sponsored by SpaceX reached the space station in May.
Friday's launch is part of NASA's ambitious program to allow private industry to take the lead in supplying the space station, thereby saving money and allowing the space agency to focus on deep space missions such as trips to Mars and asteroids. In 2011, NASA retired the final space shuttle, which the agency had used to send supplies and astronauts to the space station.
SpaceX is developing a version of Dragon to support human transport, another part of NASA's plan to transfer greater responsibility to private companies. Currently, only the Russian space agency is able to send astronauts to the space station.
Asked Friday if he was scared when it became apparent Dragon was in trouble, Musk replied: "Yes, absolutely, it was a little frightening there."
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