NASA has postponed for the second time a spacewalk by two crew members from the shuttle Discovery, this time pushing it back from Friday to Saturday, US space officials said.
The postponement aims to give mission control in Houston, Texas, more time to refine the plans for the spacewalk's goal of repairing a panel which was torn Tuesday on one wing of a solar array.
The spacewalk, the fourth of this current mission, is to be conducted by astronauts Scott Parazynski and Doug Wheelock.
If the repair is completed on Saturday, Discovery will undock from the International Space Station on schedule for a return to Earth on Wednesday November 7, when the shuttle is to land in Florida, a spokesman told AFP.
The International Space Station Program changed the priority of the fourth spacewalk from inspection of a rotary joint to repair of a solar array.
The solar panel on the International Space Station ripped as the antenna was deployed Tuesday.
The solar antenna, which has wings measuring 76 meters (249 feet) when unfurled, was repositioned after astronauts earlier successfully installed a massive truss that is used to rotate the energy-generating solar arrays.
NASA has estimated the tear in the panel to be about 90 centimeters (35 inches), but said the solar antenna nevertheless has been providing about 97 percent of the energy it supplies to the space station.
The solar array is critical to providing power for the European Laboratory scheduled for delivery in December.
A malfunctioning rotary joint was supposed to have been inspected during the spacewalk originally scheduled for Thursday, but the solar array was deemed a more urgent priority.
Officials had planned to examine the rotary joint after having found small metal shavings and unusual wear in the joint in a space walk on Sunday.
All three solar arrays have to be fully operational before a Japanese laboratory can be delivered to the ISS next spring.
The shuttle blasted off on October 23.
