The SpaceX commercial supply ship arrived at the International Space Station (ISS) on Sunday, a day later than scheduled due to thruster problems that threatened the mission's success. The unmanned spacecraft docked with the ISS at 1031 GMT, according to SpaceX, after being cleared for approach some eight hours earlier. The SpaceX Falcon 9 rocket carrying 1 ton of supplies had a flawless launch from Cape Canaveral, Florida on Friday. But flight controllers later discovered that several of the thrusters had been crippled due to clogged valve lines, stalling its planned docking with the ISS on Saturday. After several hours of fixes, orbital tests and flight maneuvers, all four thruster pods were deemed operational, according to a report of DPA. SpaceX's rockets play a vital role in resupplying the ISS following the retirement of NASA's space shuttle fleet last year. Another company, Orbital Science Corp, has a separate NASA contract to begin deliveries to the space station later this year.
