科技英语新闻:Shuttle Endeavour's launch no earlier than May 8: NASA

WASHINGTON, May 1 (Xinhua) -- The launch of U.S. space shuttle Endeavour on its final voyage will be no earlier than May 8, after technical problems uncovered last week proved more complex than originally thought, the U.S. National Aeronautics and Space Administration (NASA) announced Sunday.

NASA tried to launch Endeavour on Friday on its 25th and final flight to deliver the 2-billion-dollar Alpha Magnetic Spectrometer (AMS) particle detector to the International Space Station. AMS, a particle physics detector, is designed to search for various types of unusual matter by measuring cosmic rays. Its experiments are designed to help researchers study the formation of the universe and search for evidence of dark matter, strange matter and antimatter.

The space shuttle Endeavour sits on launch pad 39A as work continues on the shuttle's auxilliary power unit at the Kennedy Space Center in Cape Canaveral, Florida May 1, 2011.

However, the launch was called off after engineers detected a failure in one of two heater circuits associated with Auxiliary Power Unit (APU) 1. Heaters are required to keep the APUs' hydrazine from freezing on orbit.

NASA hoped Endeavour would lift off on Monday. But further trouble-shooting indicated the glitch was more complicated than officials hoped initially.

The failure appears to be a power problem within the aft load control assembly-2, a box of switches controlling power feeds.

"That basically means the power is not getting out to the heaters that weren't working on launch day," said Space Shuttle Program Launch Integration Manager Mike Moses.