This story was updated at 7:02 a.m. EDT.
Astronauts aboard the space shuttle Discovery will rest up for the trip home and may take a call from U.S. President Barack Obama Tuesday as they enter the home stretch of their mission to boost the International Space Station to full power.
Discovery skipper Lee Archambault and his crew are slated to speak with President Obama at about 9:40 a.m. EDT (1340 GMT) when he calls from the Oval Office to congratulate the astronauts on their successful construction flight, according to ABC News.
The president is expected to be joined Congressional leaders and middle school students from the Washington, D.C., area when he makes his call, ABC News reported. President Obama's call comes as he proposes a budget that includes a $2.4 billion funding boost for NASA and reaffirms a 2010 retirement date for the agency's space shuttle fleet.
The 10 astronauts aboard Discovery and the space station will also discuss their 13-day mission to deliver the last set of gleaming U.S. solar arrays and a new crewmember to the station with reporters and move some cargo between their two ships before settling into some free time before they head home.
"It's important for us to rest up the orbiter crew particular since in just a few days from now they're going to have to successfully execute a re-entry and landing," Kwatsi Alibaruho, NASA's lead station flight director for the flight, told reporters late Monday from Houston. "They've had a lot of time off coming to them."
Discovery will undock from the station Wednesday at 3:53 p.m. EDT (1953 GMT), just one day before a Russian Soyuz spacecraft is poised to blast off from the Central Asian spaceport of Baikonor Cosmodrome with a new crew and American billionaire Charles Simonyi — who is paying more than $30 million for his second trip to space. The Soyuz will arrive at the space station on Saturday, the same day Discovery is due to land in Florida.
Archambault and his crew launched March 15 after a month of delays to ferry Japanese astronaut Koichi Wakata and a $298 million pair of expansive solar wings to the space station.
Wakata is Japan's first long-term resident of the space station and will watch over the outpost's European Columbus module and Japanese Kibo laboratory, a massive orbital room the size of a tour bus, during this three-month stay. He is replacing NASA astronaut Sandra Magnus, who is completing her own four-month flight and will return to Earth aboard Discovery.
"After four months up here and having a wonderful time, I'm looking forward to being outside," Magnus said earlier this week.
Discovery's crew performed three spacewalks to install the station's fourth and final set of solar wings to complete the space station's power grid. The arrays are moored to a 16-ton girder that, when mounted to the starboard edge of the station, completed the orbiting lab's backbone-like main truss. After more than a decade of construction, the station is now 81 percent complete, longer than a football field and weighs nearly 1 million pounds.
"Overall we're absolutely thrilled and we're very happy that we were able to accomplish what we did," Alibaruho said. "We certainly accomplished our highest priority objectives, and certainly the ones that we were most concerned about were executed flawlessly without problems."
The shuttle astronauts also delivered a spare part for the space station's urine recycler, which filters astronaut urine back into pure water for drinking, food preparation bathing and other uses. They recycling system had been broken since last December, but appears to be working well after the repairs.
Mission Control roused Discovery's crew Tuesday at 6:13 a.m. EDT (1013 GMT) with the tune "Andrew's Song" by the band Treestump. The song was chosen specifically for shuttle astronaut John Phillips, whose daughter is a member of the band.
"It is great to wake up to the sounds of the Houston band Treestump, including my daughter on base guitar," Phillips radioed Mission Control. "We're looking forward to a day of getting our big motor home ready for the open road and pulling out of the driveway."
SPACE.com is providing continuous coverage of STS-119 with reporter Clara Moskowitz and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed.