Space agency says reduction will not force reworking of vehicle's external fuel tank
NASA has reduced the allowable crack size for Space Shuttle wing leading-edge reinforced carbon-carbon (RCC) panels, but does not expect the change to force a reworking of the external tank to further reduce debris size.
The space agency says the STS 114/Discovery return-to-flight (RTF) mission remains on track for launch on 15 May, with a window to 3 June, and has scheduled the second RTF mission, STS 121/Atlantis, for launch on 12 July.
But the second Shuttle could be ready for launch on a rescue mission as early as 12 June, NASA says.
Maximum RCC crack size for a safe re-entry has been reduced tenfold to 0.5mm (0.02in), which NASA says will still be detectable by the robot arm-mounted laser sensors that will be used to inspect the leading edges in orbit.
The agency says the reduction is the result of a refinement of its understanding of the damage mechanism and it does not expect to have to make further changes to the tank, the first of which is already at Kennedy Space Center having already been redesigned to minimise the size of foam debris shed during launch.
Meanwhile, NASA says it has met seven of the 15 recommendations made by the Columbia Accident Investigation Board, and progress on the final eight will be reviewed by the RTF Task Group before the final STS 114 launch decision is made. "I need to begin limiting the amount of data we request from the Shuttle programme, because they're very busy not only trying to respond to us, but getting their work done to meet the launch window," say Task Group co-chairman Richard Covey.
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
