The U.S. Space Agency NASA has postponed the next Space Shuttle launch for two more months.
Shuttle flights, suspended since the 2003 Columbia disaster, are now set to resume between July 13 and 31.
At a news conference Friday, NASA spokesmen cited several factors contributing to the delay, including continued concern about the possibility of damage by launch-related debris.
On a launch pad this month, ice buildup was found on the shuttle Discovery's main fuel tank when it was filled with liquid oxygen and hydrogen. Engineers, concerned that ice could shake loose during liftoff, are considering putting small heaters atop the tanks.
In the 2003 Columbia disaster, a piece of insulation from an external fuel tank broke off during launch, causing enough damage to the wing so that under re-entry stresses, the shuttle broke apart. All seven astronauts aboard were killed.