Video: Narrated preview of Jan. 6 spacewalk

Two space station astronauts carried out a trouble-free five-hour 58-minute spacewalk Friday, completing complex battery replacement work on the right side of the lab’s solar power truss with enough time left over to carry out a variety of lower-priority “get-ahead” tasks.

Cosmonauts Sergey Prokopyev and Dmitri Petelin floated outside the International Space Station Wednesday, unbolted an experiment airlock from the Rassvet docking compartment and then connected it to Russia’s Nauka multi-purpose laboratory module in a 7-hour, 11-minute excursion.

During a fourth spacewalk Saturday to wrap up repairs of the coolant system in a $2 billion cosmic ray detector, Italian astronaut Luca Parmitano and Drew Morgan discovered a leak in one of eight coolant lines that were spliced into a new pump module during three earlier excursions. But Parmitano was able to tighten a fitting on the line and the astronauts were able to complete the repair work, setting the stage for the instrument to resume science operations.