* Problem develops with spacecraft's rocket thruster pods
* Next opportunity for space station docking is Sunday
By Irene Klotz
CAPE CANAVERAL, Fla., March 1 (Reuters) - A rocket built by Space Exploration Technologies blasted off on Friday on a supply run to the International Space Station, but a thruster problem with the cargo ship will cause it to miss its scheduled Saturday docking, officials said.
The 157-foot (48-meter) tall Falcon 9 rocket and Dragon cargo ship lifted off at 10:10 a.m. EST (1510 GMT) from the company's leased launch pad at Cape Canaveral Air Force Station, just south of NASA's Kennedy Space Center in Florida.
The rocket delivered the Dragon capsule into its intended orbit, but within minutes engineers discovered three of the spacecraft's four rocket thruster pods were not working.
Engineers believe the problem most likely stemmed from a blockage in a pressurization system or a stuck valve, according to Elon Musk, chief executive and chief technical officer of privately owned Space Exploration Technologies, or SpaceX as the company is known.
Engineers were later able to get all four of the rocket thruster pods working. The first order of business then was to raise the capsule's obit to a higher altitude so it would not re-enter Earth's atmosphere within a day or two.
"Orbit raising burn successful. Dragon back on track," Musk posted on Twitter. NASA requires at least three thruster pods to be working before it will clear Dragon to approach the station.
The Dragon capsule, which carries more than 2,300 pounds (1,043 kg) of science equipment, spare parts, food and supplies, had been scheduled to reach the station on Saturday morning. NASA had not yet cleared SpaceX for a docking attempt. The next opportunity is Sunday.
"We have quite a bit of flexibility," NASA space station program manager Mike Suffredini said.
The cargo run is the second of 12 missions for SpaceX under a $1.6 billion NASA contract. Following a successful test flight to the space station in May 2012, SpaceX conducted its first supply run to the orbital outpost in October.
During launch of that mission, one of the Falcon's nine engines shut down early, but the other motors compensated for the power shortfall. The problem was traced to an engine material flaw, SpaceX President Gwynne Shotwell said on Thursday.
NASA's Suffredini said of that finding: "The conclusions they came to, we agree with."
"Our role as NASA is to sit next to them and work with them and understand the anomaly so that we're comfortable. We have two options as the customer: We can either put our hardware on that vehicle or not," he said.
A second space freighter, built by Orbital Sciences Corp , is expected to debut this year.
NASA turned to private companies to ferry supplies to the Space Station, a $100 billion project of 15 nations, following the retirement of the U.S. space agency's shuttle fleet in 2011. Staffed by rotating crews of six, the orbiting laboratory flies about 250 miles (400 km) above the Earth.
With the shuttles grounded, NASA plans to hire private firms to fly astronauts as well as cargo, breaking Russia's monopoly on crew transportation that costs more than $60 million per trip.
Across-the-board automatic U.S. government spending cuts going into effect late on Friday do not impact space station operations or supply runs, Suffredini said. But the cuts will slow development of privately owned space taxis, NASA said.
NASA has partnership agreements worth more than $1.1 billion through May 2014 with SpaceX, Boeing Co and privately owned Sierra Nevada Corp to develop passenger spacecraft.
Due to the cuts, NASA would effectively halt space taxi development work this summer, agency planning documents show.
Under the spending cuts, the agency expects its $17.8 billion spending plan for the current fiscal year to drop to $16.9 billion, NASA Administrator Charles Bolden wrote in a letter last month to Senate Appropriations Committee Chairwoman Barbara Mikulski.
"Overall availability of commercial crew transportation services would be significantly delayed, thereby extending our reliance on foreign providers for crew transportation to the International Space Station," Bolden wrote.