327 DAY IN THE LIFE: RISKY AND REWARDING SPACEWALKS—SPACE SHUTTLE MISSION STS-120/ISS-10A CHAPTER 18 Flight Day 12 (Saturday, November 3) – Solar Array Repair Extravehicular Activity Day The EVA was pretty spectacular. When the EVA crew members went out to the truss, they found the boom was fairly stable (Figure 20). The tip was positioned farther from the truss than it would normally be so as to not impact the truss, which created some challenging moments. The EVA crew members had to assist each other in getting back and forth to the tip, even crawling on one another’s backpack for reach (showing that even when meticulously planned, the crew and flight control team still need to adapt). The WIF Extender on the tip of the boom resulted in some flex, but the crew found it manageable. Space Station Remote Manipulator System (SSRMS) Orbiter Boom Sensor System Worksite Interface Extender (WIF Extender) Figure 20. Parazynski riding on the OBSS—“the boom”—to perform the array repair. The boom is grasped by the ISS robotic arm. The other end of the arm is grasping part of the Mobile Remote Servicer Base System on the truss. This photo was taken by the crew inside the ISS, whose main task at this time was operating the arm and monitoring the EVA crew. Wheelock is not shown in this photo because he is translating along the truss structure using his hands. Figure 21. Parazynski is being hoisted to the repair site, approximately halfway up the array. Wheelock is at the base of the array, looking up to give clearance calls so the loose array would not come in contact with his crewmate. Parazynski had an incredible 40-minute ride to the damage site, with sweeping views of the ISS from a distance. Upon arrival, he described the damage for the ground team and called it a “hair ball.” Based on this description, the team knew it would require the more complex of the repairs envisioned, and he would have to cut the long guidewire. When it came time to cut the guidewire, the video was not transmitting to the ground due to blockage of the Ku-band antenna (see Chapter 13). While the Mission Control team held its collective breath, Parazynski cut the wire and Wheelock controlled the speed as it zipped into the reel at the bottom of the array. When Wheelock reported the array had successfully retracted, the team in the control center literally cheered.