NASA on Sunday said it was continuing its countdown toward a Monday launch of the Space Shuttle Atlantis from the Kennedy Space Center here.
"We resumed the countdown (Saturday)," shuttle launch director Mike Leimbach said.
Atlantis and its team of six astronauts were scheduled to blast off at 3:46 pm (1746 GMT).
Weather forecasts were calling for a slight chance of scattered rain showers, but the US space agency said there was an 80 percent chance of favorable launch conditions.
"The weather will be very promising," meteorologist Kathy Winters predicted.
With less than 24 hours to go before launch, however, engineers were examining a slight technical problem with a hotter-than-normal heater used to prevent ice from forming in pipes that drain water from the shuttle's fuel cells.
"We're trying to understand the issue," shuttle operations manager Jim Halsell said.
Atlantis's 11-day mission aims to install a 15-meter (45-foot), 390-million-dollar arm on the space station.
Atlantis's launch was to be the first since space shuttle flights were suspended in July after cracks were discovered in the propulsion systems of all four US shuttles.
The shuttle was originally scheduled to depart Wednesday, but concerns over Hurricane Lili kept it grounded.
Power to NASA's Johnson Space Center in Houston, Texas, was cut off Wednesday to guard against damage to key computer systems ahead of the hurricane's passage.
Service has now been restored, and the center is now "fully up and mission capable. … They are ready to go," Halsell said.
