Astronauts on the International Space Station (ISS) yesterday were to examine and measure a troublesome gash in the shuttle Endeavour's heat shield by means of a camera and a laser atop a robotic arm.
The 56cm2 gouge near a landing gear hatch was apparently made by a piece of ice that broke off the shuttle's external fuel tank 58 seconds after Wednesday's launch from Cape Canaveral, Florida.
The laser device will provide the exact measurement and depth of the gash so NASA engineers can decide whether repairs are needed, for which the Endeavour mission would be prolonged to allow for an additional spacewalk.
Endeavour's mission was initially planned for 11 days, with three space walks.
NASA may extend the mission by three days, and add a space walk, after they test a new system that transfers electricity from the ISS to the orbiter, prolonging the life of the shuttle's batteries.
Separately, if NASA decides that the damaged shuttle tiles need fixing, an additional space walk is possible.
NASA on Saturday studied pictures of the damage taken on Friday, while two astronauts completed the first spacewalk of the shuttle's 11-day mission.
Mission specialists Rick Mastracchio of the US and Canadian Dave Williams spent six hours, 17 minutes installing and activating a new, 1.58 tonne segment for the International Space Station that the Endeavour had delivered.
The two astronauts attached the Starboard 5 truss segment to the Starboard 4 segment, with the help of shuttle pilot Charles Hobaugh, who from inside the ISS operated the station's robot arm holding the 3.37m x 4.24m truss.