CHAPTER 17 SYSTEMS: EXTRAVEHICULAR ACTIVITIES—BUILDING A SPACE STATION 280 Astronaut Mike Hopkins participates in the second of two US spacewalks to change out a faulty external pump on the International Space Station (ISS). Visible in his helmet visor are Rick Mastracchio (Hopkins’ partner on the spacewalk), the ISS robotic arm, and some ISS structure and solar arrays. Dec. 24, 2013. Something about seeing an astronaut in a spacesuit captures the imagination of children and adults alike. Perhaps the human shape of the spacesuit against the backdrop of Earth gives one a sense of human fragility, or maybe looking at the suit is a little like glimpsing at a futuristic human race. The general public can tell just by looking at a photo that “walking” in space while attached to the vehicle by a tenuous lifeline is one of the most dangerous pursuits. A spacewalker wears a personal spacecraft that must provide protection from the freezing cold of space, the burning heat of the sun, and the small pieces of space debris that could come hurtling at him or her at thousands of miles per hour. The reality is that astronauts and Mission Control are hyperaware of such dangers during a spacewalk.