Posted: Wed, Feb 4, 2009, 7:50 AM ET (1250 GMT)

The launch of the space shuttle Discovery later this month has been delayed at least a week to resolve an issue with a valve in the shuttle's main engines, NASA announced late Tuesday. Discovery was scheduled to launch on February 12 on mission STS-119, but that launch is now planned for no earlier than February 19 after shuttle managers completed a flight readiness review for the mission. Engineers raised concerns with a flow control valve, one of three that channel liquid hydrogen fuel to the engines, after one of them was damaged during the launch of Endeavour last November. The delay will allow additional time for testing to determine what risk any sort of debris from a cracked valve may pose to propellant lines. When it does launch, STS-119 will install the S6 truss segment on the station and deploy its solar arrays, and also exchange one member of the station's crew.