71 DAY IN THE LIFE: THE MAKING OF A MISSION CHAPTER 4 Node 3 was closed off for a couple of days, and was therefore unavailable for the astronauts to begin any outfitting. If the crew could work in Node 3 and prepare the Cupola for relocation, this task could be done during the docked shuttle mission. Four key issues had to be overcome for this to occur. First, although the modules were constructed in clean rooms, there were always small bits of debris that could not be found and removed on Earth. Once in space, these particles float freely, posing an eye injury or inhalation risk. Therefore, for the new modules, the safety engineers required the fans be up and running for some time before the crew could ingress. In this way, the filters would have time to capture all the loose debris. The second concern was that carbon dioxide and humidity would build up inside Node 3 if no airflow was present in the module furthermore, the buildup of humidity would result in condensation. Next, the module would be dark inside since the power would not be available for lights. A final issue was the inability to determine whether ammonia was somehow leaking into the cabin. Normally, the pumps and computers have sensors to detect the presence of ammonia. The ECLSS and Thermal Operations and Resources teams, with support from the BioMedical Engineer group and Boeing engineers, came up with workable solutions. The astronauts would wear eye goggles and surgical masks to prevent the debris from causing any injury, even though these options weren’t particularly comfortable. To solve the second issue, the ECLSS team combined gray tape with some unused ducting that was tucked away with another duct (one that was normally used to help pump air into the orbiter). This effort created a 7-m (23-ft) long duct that would be relocated into the Cupola during the time the astronauts were inside. If the crew members were in Node 3, they were not going to be on the orbiter. Therefore, the duct was connected to an IntraModule Ventilation fan in Node 1 and dragged into the inactive Cupola vent. Note that any cables or hoses passing through a hatchway were normally not allowed because if a catastrophic cabin leak were to occur, the crew would have to be able to exit the module and quickly close the hatch. The ECLSS team worked out a plan with the astronauts so that this could be done quickly during the small window of time in which the astronauts were inside Node 3. Portable lights ensured visibility. Finally, the team analyzed and concluded that if the ammonia was not flowing through any of the cooling lines, the risk of a leak was acceptably low enough to allow the crew to be inside the module. This mission was evolving into one of the most challenging for the ECLSS team, as it had for the OSO team. With approval from both programs, work to add these tasks to the mission began in earnest. As with any task, the PMA3 relocation grew more complicated as the team worked out additional details. With the PMA3 on the end (i.e., port side) of Node 3, the clearance between the farther port radiator panel and the module was going to be tight (Figure 5, bottom). In fact, at this point, the team didn’t even know whether there was enough clearance. When thousands of parts have been built by many different people from around the world, pinpointing the measurement of the final assembled structure was not an easy task. The size of all parts were recorded in drawings and in computer models, but verification was required to ensure everything was actually built as planned. Thermal expansion and, more critically, the flexing of the radiator panel as it moved also had to be taken into account. After careful calculation, engineers estimated that there was slightly more than 2 feet of clearance. Yet, that was true only if the calculations were right. In the event of a calculation error, the radiator and PMA3 could endure serious damage. The station team developed a conservative plan in case of calculation errors. After Node 3 was installed on the ISS with the Cupola still positioned for launch, the robotic cameras took images that were used to measure the exact clearance. Although the PMA3 was different than the Cupola, this was much closer to reality and permitted the engineering team to get more precise measurements. Images were taken from multiple positions to generate photogrammetry for a three-dimensional (3-D) model. After Node 3 was installed early in the mission, and before the team was given the green light to move the PMA3, engineers analyzed the 3-D model to ensure their preflight calculations were right. The team also had to develop a flight rule that stated under what conditions it would be “go” for the relocation. The team remained cautious. The plan was to move the PMA3 between the second and third EVA. This meant the Cupola had to be moved quickly after Node 3 was up and running to open up that berthing port for the crew to hook up the heater cables on PMA3 during the third spacewalk. Even so, the team planned to methodically move the