One of two primary satellites used by the US National Oceanic and Atmospheric Administration (NOAA) to track severe weather in the United States has failed on the eve of the 2013 Atlantic hurricane season.According to status updates posted on NOAA’s website, service from the Geostationary-orbiting Operational Environmental Satellite (GOES)-13 suffered an outage of its two main instruments on May 22. The Boeing-built spacecraft was launched in May 2006 into a storage orbit and was activated in April 2010.Experts fear the failure could not have happened at a worse time. NOAA said the satellite, which provides coverage for the entire US eastern seaboard, is relied upon to track hurricanes threatening cities along the coast. NOAA gave a warning that this year's hurricane season — the first since hurricane Sandy devastated the New York and New Jersey shorelines last October — is likely to be "extremely active".The Atlantic-Caribbean hurricane season begins this week and lasts for six months. NOAA has predicted as many as 13 to 20 tropical storms could threaten homes, with half of those likely to strengthen.NOAA typically operates two GOES spacecraft over the country, overlooking the East and West coasts, plus one on-orbit spare. The satellites are fitted with technology enabling them to watch for clouds and developing storms.The first sign of trouble with GOES-13, the primary East coast satellite, emerged late last Wednesday when it failed to relay expected images.The agency said it has activated a spare satellite to maintain East Coast coverage while attempts are made to fix the failed one, but added there was currently "no estimate on its return to operations".If a second GOES should fail, NOAA would operate its remaining satellite to get a full view of the US every half-hour. The organisation would also depend more on other information relayed by polar-orbiting weather satellites.