NASA International Space Station managers have delayed two spacewalks to replace a faulty cooling system component to Saturday and Wednesday.

Saturday's spacewalk now is officially scheduled to begin at 6:55 a.m. EDT, and will be followed by a second spacewalk Wednesday to complete replacement of the ammonia pump module that failed last Saturday.

Teams of flight controllers, engineers, and spacewalk and robotics experts have made significant progress in preparing for the spacewalk, but need an additional day to finish working out all the details.

The additional time to prepare for the first spacewalk allows for the final procedures to be uplinked late today and gives the station crew one full day to review the plans that have been developed by Mission Control. Managers also moved the second spacewalk to Wednesday to give the crew additional time to rest and prepare.