The STS-133 mission will be Discovery's final mission before retirement. It is unclear ho long it will take NASA to repair the two 7 inch cracks.
Fox News reported:
Discovery was scheduled to take off Nov. 5 on its final mission, to the International Space Station, a flight that was delayed until Nov. 30 following discovery of a fuel leak. Tuesday morning, technicians
at the space agency identified two cracks on a section of the tank’s metal exterior during removal of the external fuel tank foam insulation.
An unidentified NASA technician snapped a few high-resolution photos of the crack -- and promptly posted them on his son's blog, Gizmodo reported Tuesday evening.