NASA's long awaited return-to-flight shuttle mission has been pushed back by three days because of concern over lighting conditions during the launch window. The launch of the Discovery was slated for 12 May 2005, but will now take place on 15 May.
The space agency grounded all shuttle flights after the loss of the shuttle Columbia, and all its crew. NASA has set stringent safety conditions on any subsequent flights and one of these conditions is that there must be enough light for cameras to be able to see if any insulation foam falls off during take-off. Columbia burned-up during re-entry because its insulation tiles were damaged by a piece of foam dislodged during lift-off.
The Columbia Accident Investigation Board made 15 recommendations that have to be met for the launch to go ahead. So far, NASA has met only seven of these. However, engineers have built extra time into their schedules to meet the remaining conditions, and are confident that they will be met in time for the new launch date.