An internal flow control in the module began malfunctioning Dec.11, affecting the flow of coolant in one of the station's two cooling loops that control temperatures in equipment and experiments.

The installation work had been set for completion Monday before mission controllers detected a spacesuit configuration issue at the end of Saturday's spacewalk, when removal of the faulty module began.

Managers decided an extra day of preparation was necessary to get a backup spacesuit ready for Mastracchio, NASA said.

Tuesday's spacewalk lasted seven hours and 30 minutes.