By John Le Fevre

The crew of the space shuttle Atlantis have discovered damaged tiles on an area measuring about 21-inches (about 53cm) during an inspection prior to docking with the Hubble Space Telescope on Wednesday.

The damaged tiles span four of the space shuttles thermal tiles located on the starboard side of the craft where the wings join the forward fuselage.

Nasa flight director Tony Ceccacci said that while the initial impression was that the damage was minor, it would be analyzed by experts to ensure the space shuttles heat shield was in good condition.

Debris came off the space shuttle 104 seconds after lift off from Kennedy Space Center, Fla., on Monday.

The crew used Atlantis’ robotic arm and orbiter boom to inspect the shuttles underside and the leading edges of the wings prior to docking withe Hubble Space Telescope

The crew of the STS-125 also checked the tools they will use during five scheduled spacewalks to carry-out repairs and fit extra equipment designed to keep the telescope operating until 2014.

The servicing mission by the crew of Atlantis is the fourth maintenance trip since the Hubble Space Telescope was carried into orbit by the Space Shuttle Discovery in April 1990.

The Hubble Space Telescope is scheduled to be replaced in 2013 when the James Webb Space Telescope (JWST), is due to be launched.