An inspection of the space shuttle Atlantis has uncovered some "minor" damage to the vehicle's right side, according to NASA officials.
Atlantis appears to be in good overall shape, but NASA engineers in Houston are still studying the 53cm line of chips on its heat shield.
The shuttle was launched on Monday to begin a risky repair mission intended to repair the Hubble space telescope.
Hubble has been hit by failures to its science instruments and to gyroscopes.
The BBC reports these gyros are used to point the observatory at targets in the sky. If successful, the mission could extend Hubble's lifetime beyond 2014.
During their first full day in orbit, the crew of Atlantis used a laser-tipped boom to look for any damage to the orbiter in a 10-hour inspection.
The line of chips uncovered by the astronauts are in thick tiles that make up the protective heat shield on the shuttle's starboard side.
The damage is located where the right wing joins the shuttle's fuselage. NASA said the chips could be related to a "debris event" detected by the wing's leading edge sensors 104-106 seconds into the lift-off.