NASA engineers have decided the shuttle Endeavour need no repairs to its heat-absorbing tiles. The three-inch gouge, while causing a great deal of concern, has been deemed not to be a threat to the shuttle's safe return. Contributing to the analysis was the fact the repair itself, while it's been practiced on Earth, carries some risk - an astronaut could bump into the tiles and cause more damage during the close work required.
COMMENT: A great deal of thought went into this, and some of the media coverage was horrible, either sensationalizing the risk or bashing NASA with no effort at balanced coverage. All that said, there is no way to know with 100% certainty if this call was right until the end of the mission. All fingers will be crossed until then.