A privately operated SpaceX Dragon cargo has docked with the International Space Station after surviving a potentially critical failure.
The unmanned capsule is carrying more than 1,000 kilograms of supplies, science experiments and spare parts on behalf of Nasa for the second of its 12 planned resupply missions worth $1.6 billion in contracts.
It blasted off from Cape Canaveral on Friday atop a SpaceX Falcon 9 rocket.
But shortly after it reached orbit the craft suffered a massive failure in its thruster rocket pods, which threatened to end the mission in failure.
Three out of four of the capsule's thrusters did not activate as planned once it reached orbit.
That left the craft unable to make manoeuvres to reach the Space Station and dock with the astronauts on board.
Nasa and SpaceX said that there was a blockage in the line which pressurises the thrusters.
Space X Dragon
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This frame grab made available by NASA TV shows a view of the SpaceX Dragon anchoring to the International Space Station Sunday, March 3, 2013. SpaceX, the California-based company founded by billionaire Elon Musk, had to struggle with the Dragon following its launch Friday from Cape Canaveral. The spacecraft is delivering more than 1 ton of supplies to the the International Space Station. (AP Photo/NASA TV) (credit:AP)
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This frame grab made available by NASA TV shows a view of the SpaceX Dragon capsule on the end of the International Space Station's robotic arm, Sunday, March 3, 2013. SpaceX, the California-based company founded by billionaire Elon Musk, had to struggle with the Dragon following its launch Friday from Cape Canaveral. The spacecraft is delivering more than 1 ton of supplies to the the International Space Station. (AP Photo/NASA TV) (credit:AP)
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The Falcon 9 SpaceX rocket lifts off from launch complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla. on Friday, March 1, 2013. The rocket is transporting the Dragon capsule to the International Space Station containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/John Raoux) (credit:AP)
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People photograph the Falcon 9 SpaceX rocket as it lifts off from launch complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla. on Friday, March 1, 2013. The rocket is transporting the Dragon capsule to the International Space Station containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/John Raoux) (credit:AP)
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The Falcon 9 SpaceX rocket lifts off from launch complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla., Friday, March 1, 2013. The rocket is transporting the Dragon capsule to the International Space Station containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/John Raoux) (credit:AP)
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The Falcon 9 SpaceX rocket lifts off from launch complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla., Friday, March 1, 2013. The rocket is transporting the Dragon capsule to the International Space Station containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/John Raoux) (credit:AP)
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The unmanned Falcon 9 SpaceX rocket lifts off from launch complex 40 at the Cape Canaveral Air Force Station in Cape Canaveral, Fla., Friday, March 1, 2013. The rocket will transport the Dragon capsule to the International Space Station containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/John Raoux) (credit:AP)
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In a photo provided by NASA, the SpaceX Falcon 9 rocket, with it's Dragon spacecraft onboard, is seen shortly after it was erected at Launch Complex 40 at the Cape Canaveral Air Force Station in Florida on Friday, March 1, 2013. Launch of the second SpaceX Commercial Resupply Services mission is scheduled for later Friday morning. (AP Photo/Nasa, Bill Ingalls) (credit:AP)
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This Jan. 12, 2013 photo provided by NASA shows the Dragon spacecraft inside a processing hangar at Cape Canaveral Air Force Station in Cape Canaveral, Fla. where teams had just installed the spacecraft's solar array fairings. The California company known as SpaceX is scheduled to launch its unmanned Falcon rocket on Friday morning, March 1, 2013, carrying a Dragon capsule containing more than a ton of food, tools, computer hardware and science experiments. (AP Photo/NASA, Kim Shiflett) (credit:AP)
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FILE - This Thursday, May 24, 2012 image made from video provided by NASA-TV shows the International Space Station taken from the thermal imaging camera aboard the SpaceX Dragon commercial cargo craft as it approaches the station. The International Space Station regained contact with NASA controllers in Houston after nearly three hours of accidental quiet, the space agency says. Officials say the six crew members and station are fine and had no problem during the brief outage. A spokesperson said something went wrong during a computer software update on the station. (AP Photo/NASA) (credit:AP)
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This photo provided by SpaceX shows an unmanned Dragon freighter that left the International Space Station with a stash of precious medical samples and aimed for a Pacific splashdown to end the first official shipment under a billion-dollar contract with NASA, Sunday, Oct. 28, 2012. Astronauts aboard the International Space Station used a giant robot arm to release the commercial cargo ship 255 miles up. The California-based SpaceX company steered its capsule back to Earth via parachutes on Sunday afternoon, a couple hundred miles off the Baja California coast. (AP Photo/SpaceX) (credit:AP)
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In this image provided by NASA the SpaceX Dragon commercial cargo craft is berthed to the Earth-facing side of the International Space Station's Harmony node Wednesday Oct. 10, 2012. Working from the robotics workstation inside the seven-windowed Cupola, Japan Aerospace Exploration Agency astronaut Aki Hoshide, Expedition 33 flight engineer, with the assistance of NASA astronaut Sunita Williams, commander, captured Dragon at 6:56 a.m. (EDT). Dragon is scheduled to spend 18 days attached to the station. During that time, the crew will unload 882 pounds of crew supplies, science research and hardware from the cargo craft and reload it with 1,673 pounds of cargo for return to Earth. After Dragon's mission at the station is completed, the crew will use Canadarm2 to detach Dragon from Harmony and release it for a splashdown about six hours later in the Pacific Ocean, 250 miles off the coast of southern California. It's the first official delivery by the California-based SpaceX company under a $1.6 billion contract with NASA. (AP Photo/NASA) (credit:AP)
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In this image provided by NASA the SpaceX Dragon commercial cargo craft is grappled by the International Space Station's Canadarm2 robotic arm Wednesday Oct. 10, 2012. Working from the robotics workstation inside the seven-windowed Cupola, Japan Aerospace Exploration Agency astronaut Aki Hoshide, Expedition 33 flight engineer, with the assistance of NASA astronaut Sunita Williams, commander, captured Dragon at 6:56 a.m. (EDT). Dragon is scheduled to spend 18 days attached to the station. During that time, the crew will unload 882 pounds of crew supplies, science research and hardware from the cargo craft and reload it with 1,673 pounds of cargo for return to Earth. After Dragon's mission at the station is completed, the crew will use Canadarm2 to detach Dragon from Harmony and release it for a splashdown about six hours later in the Pacific Ocean, 250 miles off the coast of southern California. It's the first official delivery by the California-based SpaceX company under a $1.6 billion contract with NASA. (AP Photo/NASA) (credit:AP)
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This image from NASA-TV shows the capture of the Dragon capsule by a robot arm on the International Space Station as they passed over the South Atlantic Ocean early Wednesday Oct. 10, 2012. It's the first official delivery by the California-based SpaceX company under a $1.6 billion contract with NASA. The contract calls for 12 such shipments. (AP Photo/NASA) (credit:AP)
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This image from NASA-TV shows the capture of the Dragon capsule by a robot arm on the International Space Station as they passed over the South Atlantic Ocean early Wednesday Oct. 10, 2012. It's the first official delivery by the California-based SpaceX company under a $1.6 billion contract with NASA. The contract calls for 12 such shipments. (AP Photo/NASA) (credit:AP)
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In this image provided by NASA the Space Exploration Technologies Corp., or SpaceX, Falcon 9 rocket with it's Dragon capsule attached on top is seen at Space Launch Complex-40 at Cape Canaveral Air Force Station in Florida Oct. 2, 2012. The coming mission is the first under a $1.6 billion contract with NASA that calls for a dozen resupply flights by SpaceX, essential in the post-shuttle era. The liftoff is planned for Sunday morning, Oct. 7, at 8:35 p.m. EDT. (AP Photo/NASA) (credit:AP)
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This undated computer generated illustration provided by SpaceX shows a Dragon Crew spacecraft in Earth orbit showing solar panels in the process of deploying. NASA has picked three aerospace companies to build small rocketships to take astronauts to the International Space Station. This is the third phase of NASA's efforts to get private space companies to take over the job of the now-retired space shuttle. The space agency is giving them more than $1.1 billion. Two of three ships are capsules like in the Apollo era and the third is a lifting body that is closer in design to the space shuttle. (AP Photo/SpaceX) (credit:AP)
Charles Bolden, Elon Musk(18 of22)
NASA Administrator Charles Bolden, left, and SpaceX CEO Elon Musk, right, answer questions in front of the SpaceX Dragon spacecraft Wednesday June 13, 2012 at the SpaceX Rocket Development Facility in McGregor, Texas. The spacecraft recently made history as the first commercial vehicle to visit the International Space Station. The California-based SpaceX is the first private business to send a cargo ship to the space station. (AP Photo/Waco Tribune-Herald, Duane A. Laverty) (credit:AP)
Charles Bolden(19 of22)
NASA Administrator Charles Bolden gets a close up look at the SpaceX Dragon spacecraft Wednesday June 13, 2012 at the SpaceX Rocket Development Facility in McGregor, Texas. The spacecraft recently made history as the first commercial vehicle to visit the International Space Station. The California-based SpaceX is the first private business to send a cargo ship to the space station. (AP Photo/Waco Tribune-Herald, Duane A. Laverty) (credit:AP)
Elon Musk(20 of22)
SpaceX CEO Elon Musk answers questions in front of the SpaceX Dragon spacecraft Wednesday June 13, 2012 at the SpaceX Rocket Development Facility in McGregor, Texas. The spacecraft recently made history as the first commercial vehicle to visit the International Space Station. The California-based SpaceX is the first private business to send a cargo ship to the space station. (AP Photo/Waco Tribune-Herald, Duane A. Laverty) (credit:AP)
Charles Bolden(21 of22)
NASA Administrator Charles Bolden gets a close up look at the SpaceX Dragon spacecraft Wednesday June 13, 2012 at the SpaceX Rocket Development Facility in McGregor, Texas. The spacecraft recently made history as the first commercial vehicle to visit the International Space Station. The California-based SpaceX is the first private business to send a cargo ship to the space station. (AP Photo/Waco Tribune-Herald, Duane A. Laverty) (credit:AP)
Elon Musk(22 of22)
SpaceX CEO Elon Musk answers questions in front of the SpaceX Dragon spacecraft Wednesday June 13, 2012 at the SpaceX Rocket Development Facility in McGregor, Texas. The spacecraft recently made history as the first commercial vehicle to visit the International Space Station. The California-based SpaceX is the first private business to send a cargo ship to the space station. (AP Photo/Waco Tribune-Herald, Duane A. Laverty) (credit:AP)
After several hours of troubleshooting, however, the thrusters were brought back online. Space X founder Elon Musk said that there was "no leakage" and described the problem as a "glitch".
"It was a little frightening there," he admitted.
The Dragon eventually docked with ISS on Sunday, when station commander Kevin Ford used a Canadian-built robotic arm to grab the capsule.
"It's not where you start but where you finish that counts. You guys really finished this one on the mark," Ford told the SpaceX team back in California.
"What a fantastic day."
The capsule will now be unpacked over several days - but a gift of fresh fruit placed in the craft by its president will be eaten at once.
It will then be reloaded with 1,300 kilograms of spent supplies and scientific samples before heading back to Earth.
Another firm - Orbital Sciences Corp - will send its out privately-built resupply capsule to the ISS later this year.