Shuttle grounded by robot arm trouble on Alpha

Problems with the space station's robot arm, hanging in a 'V' below Alpha, have delayed the shuttle launch

(CNN) -- The launch of the space shuttle Atlantis has been postponed while NASA evaluates a problem with the new robot arm on space station Alpha.

The arm is needed to carry out the primary objective of the shuttle mission -- the installation of a new U.S.-built airlock on the space station.

During tests by space station crew members, Russian commander Yury Usachev and U.S. astronauts Jim Voss and Susan Helms, a backup electronics box near the arm's elbow failed to work properly. Efforts to fix the problem with software patches uploaded by ground controllers have failed.

"We've decided to postpone to no earlier than early July because of problems on the station with the newly delivered arm," said NASA spokesman Bruce Buckingham.

Buckingham said NASA is evaluating options for fixing the arm. Those options may include expanding the tasks on a scheduled June 8 "internal spacewalk" by Alpha crew members Usachev and Voss.

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The pair was to work inside the space station with the hatch open to move a docking mechanism in the Zvezda module, in order to prepare for the arrival of a Russian docking module later this summer. Mission managers may add arm repair work to the list of duties.

The delay in the launch of Atlantis means NASA also will push back the next mission, the launch of Discovery. That mission was scheduled for July 12 to deliver a new crew to Alpha, but now it will go up no earlier than August.

The Alpha crew: Jim Voss, left, Yury Usachev, center, and Susan Helms

The Atlantis mission also may be revised to include work on the arm.

The launch of Atlantis already had been delayed from June 14 to June 20 because of soggy thermal tiles. Workers finished drying the tiles over the weekend and the shuttle was moved Tuesday to the Vehicle Assembly Building at Kennedy Space Center to complete launch preparations.

Atlantis got soaked in a rare desert downpour after landing at Edwards Air Force Base in the Mojave Desert on February 20.

Water on the tiles could have frozen as the shuttle reached orbit, possibly causing the tiles to come off. The 22,000 heat protection tiles shield the shuttle from the 3,000-degree Fahrenheit temperatures encountered during reentry into Earth's atmosphere for landing.