Michael Hopkins is a 1991 engineering graduate who was also a co-captain of the school's football team. He's making the repairs Tuesday along with astronaut Rick Mastracchio.
NASA ordered up the spacewalks to revive a critical cooling loop at the International Space Station. All nonessential equipment had to be turned off when the line conked out Dec. 11, and many science experiments halted.
Mastracchio and Hopkins removed a faulty ammonia pump during Saturday's spacewalk. On Tuesday, they worked to install a new pump 260 miles above the planet.
Hopkins has been on the space station for about seven months in what is his first space flight.