NASA Shuttle Discovery: Extra flights in jeopardy

Space shuttle Discovery moves out of the cavernous Vehicle Assembly Building for the last time on Sept. 20, 2010 to prepare for its final mission to the International Space Station. Credit: NASA/Jack Pfaller

Less than two weeks before the space shuttle Discovery is scheduled to launch on its last flight, uncertainty still remains as to exactly when NASA's very final orbiter mission will fly, bringing the storied shuttle era to a close next year. 
 
NASA has two scheduled shuttle missions, on Discovery and Endeavour, left to fly before retiring its orbiter fleet in 2011. 


A third, extra shuttle mission has been approved by Congress and President Obama, but still faces review by congressional appropriators later this year. 


But NASA's shuttle program manager John Shannon told reporters Thursday (Oct. 21) that definitive plans have not yet been made as to whether the potential third and final shuttle mission will fly to the International Space Station. [Gallery: Shuttle Discovery's Last Launch Pad Trip]