Space Shuttle Discovery Gets Patch Job

NASA engineers are working to bolster weak spots in space shuttle Discovery's external fuel tank, which has been plagued by cracks that developed during a previous launch attempt.

Space Shuttle Discovery

The engineers are modifying the tank by adding support structures to beams, known as stringers, that surround the tank. The cracks have kept Discovery grounded since last November.

"It's been a long road," said shuttle program manager John Shannon. "Additional support structures called radius blocks are being added to 94 stringers, meaning the entire circumference of the external tank will be strengthened by the time all the repairs and modifications are finished," Shannon said.

Discovery will lift off on its final mission no earlier than February 24, NASA said.

The shuttle program will wind down this year as NASA, under a directive from President Obama, turns launches to the International Space Station over to private contractors such as Space Exploration Technologies Corp. Obama has said the plan will cut costs while allowing NASA to focus on long-term goals such as a manned mission to Mars, but critics say it could cost jobs and leave the U.S. lagging behind Russia and China in the space race.

Discovery's current mission, officially known as STS-133, is scheduled to be its last. When it finally lifts off from Florida's Kennedy Space Center bound for the ISS, it will carry a six-member, all-U.S. crew. The team is led by Commander Steve Lindsey, 50, of Temple City, Calif., and pilot Eric Boe, 45, of Atlanta. Also on board will be mission specialists Alvin Drew, 47, of Washington, D.C., Tim Kopra, 47, of Austin, Texas, Michael Barratt, 51, of Camas, Wash., and Nicole Stott, 47, of Clearwater, Fla.

Discovery entered service in 1984, and is one of three remaining shuttles of the six originally built. Atlantis and Endeavour remain in service, while Challenger and Columbia were lost in accidents that claimed the lives of their crewmembers. The first shuttle, Enterprise, was a test vehicle that was retired shortly after its initial series of suborbital flights in 1977.

The shuttle Endeavour will make what may be the final flight of the program when it takes to the skies on a mission currently slated for April 1. Planning for that mission, STS-134, is, however, complicated by the fact that mission commander Mark Kelly is the husband of Rep. Gabrielle Giffords. Giffords was shot Saturday by a derangement gunman and is currently hospitalized in Arizona, with Kelly at her side.

NASA has said it is taking the situation day by day.