Extra shuttle mission this year in doubt

CAPE CANAVERAL, Fla., Jan. 14 (UPI) -- Delays in the space shuttle Discovery's mission for repairs to its fuel tank raise doubts about an extra shuttle mission this year, U.S. officials say.

Two more shuttle trips were planned before the aging three-orbiter fleet was to be retired when a third, final mission was approved by Congress last year in a NASA authorization bill signed by President Barack Obama, SPACE.com reported.

But funding for the measure has not been appropriated as the country operates under a continuing resolution, freezing NASA at 2010 funding levels until Congress can agree on a formal budget.

Sen. Bill Nelson, D-Fla., said the issues with Discovery's fuel tank and its ongoing repairs don't bode well for the extra mission.

"If worst came to worst and they felt like this tank was not safe, they would stand down and at that point would only fly two more shuttle flights instead of the three that are authorized," Nelson said.

If Discovery's tank is determined by NASA to be unusable, there are no spares, just the two remaining tanks reserved for the other two missions.

If Discovery's tank cannot be fixed, Nelson says that NASA might cancel the extra, third mission and use the tank allocated for it on the upcoming launch of Discovery.