According to Arianespace, the Ariane 5 rocket's Vulcain main engine ignited as scheduled（安排） at 5:45 pm EDT (21:45 GMT), but the checkout process during ignition detected an unspecified anomaly, shutting down the engine before the two solid-rocket boosters ignited.

    The 165-foot (50-meter) tall Ariane 5 rocket's main engine's checkout process "was not completed successfully, preventing the boosters' ignition and thereby aborting the mission," Arianespace officials said. "The Ariane 5 and its two payloads remain in a safe mode on the launch pad."The Ariane 5 rocket uses a Vulcain 2 first stage engine assisted by two solid rocket boosters to launch satellite payloads into orbit. The Vulcain 2 engine is fueled by cryogenic liquid hydrogen and liquid oxygen and is designed to burn for about 600 seconds to boost payloads into space.

    Jean-Yves Le Gall, Arianespace president, said it would return the rocket to the final assembly building to prepare it for another launch attempt while investigating the cause of the problem. No new launch date was immediately announced.

    The Ariane 5 was to launch the Yahsat Y1A and Intelsat New Dawn communications satellites.（本文由在线英语听力室整理编辑）