CHAPTER 18 DAY IN THE LIFE: RISKY AND REWARDING SPACEWALKS—SPACE SHUTTLE MISSION STS-120/ISS-10A 326 WARNING WARNING WARNING Minimize contact between metal array components and exposed damaged solar cells on active side. Note some sparking may be expected. Avoid contact with solar panels except with insulated tools. Sharp edges likely present at damage locations. 1. Verify glove gauntlets cover wrist disconnects 1. Sharp edges: a. SABB (skirt, swing bolts) b. Solar cells c. Springs along tension bar d. Panel hinges e. Guide cable burrs or frays f. Mast Canister roller guides g. Braided cables h. Fastener exposed threads i. Exposed bolts in rib cavities on mast canister 2. Shock hazard: a. Avoid EMU contact with FCC and Kapton part of solar array panels b. EV crew will only contact energized surfaces with approved tools that have been insulated with Kapton tape to prevent molten metal and shock c. Solar array to be manipulated will be shunted prior to EV crew entering worksite 3. Pinch: a. Lower SABB exposed reels and pulleys (guide wire and tensioning mechanisms) b. Solar array mast during deploy/retraction 4. Avoid inadvertent contact with: a. SSU, ECU, beta gimbal platform, mast canister, SAW blanket boxes unless the beta gimbal is locked and the motor is turned off Figure 18. Detailed warnings sent up to crew to study in advance of the EVA. (SABB = Solar Array Blanket Box EMU = Extravehicular Mobility Unit FCC = Flat Collector Circuit SSU = Sequential Shunt Unit ECU = Electronics Control Unit SAW = Solar Array Wing) Upper Blanket Box STBD PORT Lower Blanket Box Small Damage Cuff#1- Medium STIFF#1 STIFF#2 STIFF#3 STIFF#4 STIFF#5 STIFF#6 40 39 38 37 36 35 34 33 32 Cuff#2- Short Cuff#3- Long Cuff#4- Short Cuff#5- Medium Large Damage EV1 EVA 4 Cuff Checklist – Page 1 Figure 19. Graphics that the crew printed out on board and taped to Parazynski’s cuff checklist. He could look down at his wrist to make sure he knew exactly where each end of each cufflink was installed. The nomenclature “stiff” refers to strips of material called “stiffeners” that run the length of the blankets, somewhat helping to rigidize the array. These and the bay numbers 32 through 40 were there to help the control center and crew have a common nomenclature if they noted an issue with a particular area. None of the bay numbers were physically marked on the arrays.