NASA flight engineer Kate Rubins and Japan Aerospace Exploration Agency astronaut Soichi Noguchi exited the station on Friday shortly after 6:30 a.m. ET in a continuation of the effort to ready the station for solar array upgrades. Four pairs of solar panels soak up the sun’s energy to provide electrical power to ISS systems and the arrays are now showing signs of degradation after operating for decades. The panels are designed for a 15-year service life and the first pair was deployed in December 2000, with additional pairs delivered in 2006, 2007 and 2009. Rubins and Noguchi will spend 6.5 hours outside the ISS to complete several tasks including venting ammonia from the Early Ammonia System and installing a "stiffener" device on the Quest airlock thermal cover.