NASA will postpone the launch of the Space Shuttle Atlantis from Thursday to Friday to solve an electrical problem, a spokesman for the US space agency said.
"The mission management team has decided to postpone another 24 hours a launch and come back on Friday to work at this problem," said National Aeronautics and Space Administration spokesman Dean Acosta, giving no further details.
Earlier on Wednesday a NASA spokesman said that Atlantis's launch had been delayed until Thursday because one of the three fuel cells providing electricity to the shuttle had malfunctioned.
A failure to launch this week could delay the Atlantis mission until late October.
Bad weather last week scuttled three attempts to launch Atlantis on its 11-day mission to the International Space Station.
The mission is to be Atlantis's first ISS construction mission in nearly four years.
The agency plans to undertake 16 shuttle missions to complete the complex assembly of the half-finished space station by 2010, when the three-shuttle fleet is set to retire.