This story was updated on Dec. 10 at 3:15 p.m. ET.
NASA has delayed the launch of its new infrared sky mapper by at least a day, with liftoff now scheduled for no earlier than Saturday.
The Wide-field Infrared Survey Explorer (WISE) is now slated to launch on Dec. 12 between 9:09:33 and 9:23:51 a.m. EST (1409 and 1423 GMT) from California's Vandenberg Air Force Base.
The flight was already threatened by cloudy weather predictions for Friday, and now NASA has decided to push back the launch to allow engineers to troubleshoot a glitch in a booster steering engine on the Delta II rocket slated to carry the observatory to orbit.
Unfortunately, thick clouds and rain are still forecasted for Saturday, with an 80 percent chance of bad weather likely to prevent the launch.
"We've got some challenging weather ahead of us," said launch director Chuck Dovale during a Wednesday briefing.
If the spacecraft cannot launch Saturday, NASA will likely stand down for two days to allow the cryogenic cooling systems on WISE to cool back down, and then try again. Conditions do look better for a launch attempt next week.
"The weather finally starts to clear and break up for Monday and into Tuesday," said NASA weather officer Capt. Andrew Frey, Jr.
Other than cloud concerns, the observatory is in good shape and prepared for its mission, managers said.
"I can report that the instrument and the satellite is ready to go, the flight team is ready to go, and that the operations team is ready to launch and operate WISE," said Bill Irace, WISE project manager. "We're really excited about this. It's a matter of just the weather now."
The $320 million spacecraft was designed to scan the heavens in long-wavelength infrared light, which can reveal dim stars, dark asteroids and other celestial objects that shine faintly in visible light but more brightly in infrared.
The orbiter will scan the entire sky with a wide field of view to create an all-sky map of infrared light in about six months.
"It will represent the infrared motherlode that astronomers will mine for years to come," said Jon Morse, director of astrophysics at NASA.
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