Expedition 63 Commander Christopher Cassidy and Joint Operations Commander Robert Behnken, both NASA astronauts, completed the three and a half year process of upgrading the International Space Station’s power systems during a spacewalk on July 21st.
The spacewalk, designated US EVA-68, marked the 10th EVA for both astronauts, who have each accumulated over 50 hours of spacewalking time each during their respective careers.