Ongoing fuel engine sensor problems forced the US space agency NASA on Sunday to cancel the launch of the shuttle Atlantis and postpone any further attempt until January at the earliest, according to dpa. Work had already begun on refuelling the shuttle tanks in hopes of a 2021 GMT launch on an 11-day mission to take the European Space Agency space laboratory Columbus into space. About eight hours before the launch from Kennedy Space Center in Cape Canaveral, however, the agency said an engine-cutoff sensor failed while the external tank was being filled. It was the second launch postponement, further reducing the window - till December 13 - for an Atlantis mission before the end of the year. Now, NASA said the earliest possible launch date was January 2. The launch has already been delayed by two days since Thursday's original target date after problems emerged with a fuel cut-off sensor system inside the shuttle and its external fuel tank. Two of four fuel engine-cutoff sensors failed to function on the shuttle Atlantis' external fuel tank during fuelling on Thursday, falling short of the stringent NASA safety requirements that three of four sensors operate properly, NASA officials said. Those standards had been upped to four of four for Sunday's launch by NASA officials mindful of ignored warnings from engineers before the 2003 Columbia disaster that claimed seven astronauts' lives. "If we don't have four of four, we'll scrub," NASAs Leroy Cain, who oversees shuttle operations at the Florida spaceport, had said on Saturday. The sensor system helps protect the shuttle's three main engines by triggering their shutdown if fuel runs unexpectedly low - an event that could lead to overheating and an explosion, NASA officials explained. Fuel sensor problems have caused considerable launch delays since the retooling of troublesome tanks after the 2003 disaster. NASA officials spent the past three days reviewing data on the problem and debating the launch. The crew on the journey to the station orbiting 400 kilometres above Earth include German astronaut Hans Schlegel, French astronaut Leopold Eyharts and five US astronauts. The mission marks the beginning of a new chapter in international space flight that is to give Europe its first real foothold in space with the installation of the ESA laboratory. Space travel has been dominated by Russia and the United States for half a century. The ESA lab, built mostly by EADS-Astrium in Bremen, Germany, was supposed to go into operation in 2004. But when the space shuttle Columbia disintegrated on re-entry into Earth's atmosphere in 2003, killing all seven astronauts on board, shuttle flights were suspended. The 13-ton, 880-million-euro (1.3-billion-dollar) Columbus module has seven fixed racks that will accommodate experiments ranging from medical to material research - from the study of single-cell organisms and invertebrates to the basic physics of fluids. The installation will take several spacewalks.
