NASA has extended the Space Shuttle Atlantis mission from 11 days to 13 days to attempt to fix a tear of at least four inches in the shuttle's Thermal Protection System (TPS), which occurred during liftoff on June 8. A fourth spacewalk is also planned to take place.

The tear was discovered when astronauts used the shuttle's robotic arm with digital cameras placed on the end.

NASA says that the tear is not a major concern for re-entry, but they want to fix the problem before Atlantis returns, to reduce the amount of possible repairs Atlantis might need.

"I don't want to take the risk of damaging my flight hardware," said chairman of Atlantis's mission management team, John Shannon. Shannon said that it was unlikely that the tear would result in a disaster similar to that which occurred with the Space Shuttle Columbia which was lost in 2003 during re-entry.

Atlantis will now return to Earth on June 21, rather than the original return date of June 19.