New from the space: astronauts repair Discovery before going back

The plans for Monday's spacewalk lacked the drama of the astronauts' jaunt on Saturday, when they stood on the end of 100 feet (30 meters) of a sometimes-oscillating shuttle robotic arm connected to an extension boom. They were testing its sturdiness for making repairs to the space shuttle.

Photo: New from the space: astronauts repair Discovery before going back

Their more mundane tasks this time involved installing a spare external pump compartment to the station's cooling system and replacing a severed cable that provides power, video and data to the space station's rail car.

The spacewalk, arriving at the middle of space shuttle Discovery's 13-day mission, was expected to last under seven hours, the AP reports.

Replacing the cable on the rail car, or mobile transporter, is crucial for the continuation of construction of the space station. The cable was accidentally severed last December by a cable cutter. During Saturday's spacewalk, the astronauts immobilized a cable cutter on a duplicate cable leading to the transporter.