This story was updated Feb. 7 at 4:09 a.m. ET.
CAPE CANAVERAL, Fla. — NASA fueled the space shuttle Endeavour for the mother of all Super Bowl pregame shows — a predawn blastoff on Sunday that is expected to be the last night launch of an orbiter ever.
Endeavour and a crew of six astronauts are slated launch toward the International Space Station from a seaside pad here at NASA's Kennedy Space Center. Liftoff is set for 4:39 a.m. EST (0939 GMT), about 14 hours before the Indianapolis Colts and New Orleans Saints kick off Super Bowl 44 in South Florida.
"It's going to be a special day," said shuttle launch director Mike Leinbach. "We're going to launch Sunday morning and we're going to watch the big game Sunday night."
Despite a promising weather forecast, which predicted an 80 percent chance of clear skies, NASA has been battling a thick, low cloud layer that has been threatening the planned liftoff. If the launch is delayed, NASA will gladly skip the Super Bowl to get Endeavour ready to fly on Monday.
"We're not going to change our plans based on the Super Bowl, frankly," Leinbach said, adding that tomorrow's game is not the first — or the last — football championship game. "So there have been quite a few, and there will probably be more."
Fueling operations began a bit late due to a glitch with equipment on Endeavour's launch pad gantry. NASA began pumping super-cold liquid oxygen and liquid hydrogen propellant into the shuttle's 15-story external tank at about 7:47 p.m. EST (0047 GMT).
Endeavour's planned 13-day mission is the first of NASA's five final shuttle missions before the space agency retires its aging orbiter fleet later this year. It is NASA's last major construction job to build the 11-year-old station.
The shuttle will deliver a new room to the station along with a dome-shaped observation portal lined with windows. They will be installed during three spacewalks by the astronauts, who will be following an overnight work shift.
The predawn shuttle launch is also expected to be the last ever to blast off in darkness.
"It should be spectacular," said Endeavour commander George Zamka, who will make his second trip to space on the mission. [How to see the shuttle launch.]
At liftoff, Endeavour's twin solid rocket boosters will light up the night sky, Zamka said. That?s the first thing Florida skywatchers will see. The rumbling roar of the shuttle?s rocket engines will reach the crowds a short time later as Endeavour climbs into the morning sky.
"It's going to light up the ground around," he said. "You should be able to see it from as far as the Carolinas, I think, if the skies are clear. It should be a wonderful sight." In fact, experts say the shuttle could be visible from as far away as New York if the skies are clear enough.
Set to launch spaceward on Endeavour with Zamka are shuttle pilot Terry Virts and mission specialists Kathryn Hire, Stephen Robinson, Robert Behnken and Nick Patrick. All are veteran spaceflyers with the exception of Virts, who is making his first spaceflight.
Space rooms and windows
Zamka's five-man, one-woman crew will deliver the station's new Tranquility module and a seven-window observation portal dubbed the Cupola. Once they're installed, the $100 billion station will be about 98 percent complete. Construction began in 1998.
Tranquility is a new $382 million room designed to house the station's life support and exercise gear, as well as a robotic arm control station. The Cupola is a $27.2 million dome with six windows arranged around a large central portal for optimum viewing of the Earth and space.
Both Tranquility and the Cupola were built by the European Space Agency (ESA), which has sent more than 100 people to come watch Endeavour launch their handiwork into space.
"It's a lot like a baby growing up, a child leaving the house," said ESA space station program manager Bernardo Patti.
Endeavour's flight comes less than a week after President Barack Obama ordered NASA to scrap its current plan to replace the shuttle fleet with new Orion spacecraft and their Ares rockets to send American astronauts into space and on to the moon.
Instead, the administration released a 2011 budget request for NASA that would set aside funding to develop new technologies and support commercially built spacecraft that could send astronauts back to the moon — or to asteroids or Mars — faster than the old path.
Shuttle officials said the radical shift has left some workers in shock, but they are still focused on the near-term goal of launching Endeavour safely.
"It's kind of one of those uncertainties about where we're going to go next," said Mike Moses, NASA's shuttle launch integration manager.
Sunday's launch will mark the 34th flight for Endeavour and is NASA's 130th shuttle mission since its reusable space planes began launching in 1981.
"It's going to be a beautiful launch. You'll be able to see it all the way up the East Coast and we're looking forward to it," Leinbach said. "The team is energized. We're ready to go."
SPACE.com is providing complete coverage of Endeavour's STS-130 mission to the International Space Station with Managing Editor Tariq Malik in Cape Canaveral and Staff Writer Clara Moskowitz in New York. Click here for shuttle mission updates and a link to NASA TV. Live coverage begins at 11:30 p.m. ET.