BEIJING, Aug. 21 (Xinhuanet) -- NASA technicians on Sunday successfully replaced two bolts securing a crucial communications antenna on space shuttle Atlantis because engineers thought they were dangerously short.

Atlantis isscheduled tolift offon the upcoming Sunday on a mission to resume construction of the International Space Station.

The work began Friday evening and wrapped up Sunday afternoon. "Everything went well and we're good to go," NASA spokeswoman Tracy Young said.

Atlantis has safely flown 26 times with those bolts since they were first installed 25 years ago. The problem was discovered after Atlantis was rolled to the launch pad when a review of paperwork on bolts on NASA's three space shuttles was ordered because a related problem was found in Discovery.

NASA decided to swap two of the four bolts holding Atlantis' main communications antenna in place because they weretoo short, and liable to pop out duringlaunch with potentially catastrophic results.

Atlantis and its six crew are due to carry a 16 ton truss segment that contains the space station's second set of solar arrays. The power upgrade is expected to double the amount of electricity available for the station. Enditem

(Agencies)