CHAPTER 10 DAY IN THE LIFE: PREPARING FOR THE UNEXPECTED 188 of the sim was an issue with the LA-1 MDM. It had not completely died, but instead was still operating however, the computer circuit that allowed it to talk to its bus controller—i.e., the Internal MDM (see Chapter 5)—was not operating. Thus, the LA-1 MDM still tried to control its pumps and valves, but the rest of the system could not talk to it. This MDM managed the LTL accumulator quantity. Normally, if the liquid in that accumulator increases, it means water from the other loop or from the ammonia line is leaking into the system. Yet, those data could not be reported because of the communication failure with the Internal MDM. However, in this sim case, those data could not trigger an automated alarm. The crew smelled the ammonia and pressed the manual alarm. Since the flight control team failed to fully recognize the configuration and the full implications, the CTO decided to change the sim plan and insert an ammonia leak. By the time a person smells ammonia, there is a significant chance it is too late because of the toxicity. Since the crew is well trained to perform a memorized response, indication that the hatches were not in their expected sealed position followed by the lack of response by the crew when called did not bode well. Yet, no one on the flight control team acknowledged that fact. Furthermore, the LA-1 MDM controls the Loop Crossover Assembly (see Chapter 11), which allows the thermal loops to be separated into two independent loops (i.e., dual). Since the flight controller did not recognize this issue, the attempts to transition to dual mode were failing. The team lost precious time since this transition was never going to succeed. In some areas, team coordination and communications during this simulation worked well. ETHOS, SPARTAN, CRONUS, and ADCO worked very well with regard to the solar arrays. They realized that if the loops were vented, the ISS could lose gyro control and would need to hand over to the power attitude thrusters of the Russian Segment. Before this could be done, the massive solar arrays had to be put into a safe configuration. This, in turn, required the PTR MDM to be recovered. Although the team did everything in its power to save the crew, this simulation drove home that mistakes and failures can put crew members at risk or get them killed. Simulations such as this emphasize the need for vigilance, responsibility, and competence to the flight controllers. Lives are in their hands, and this can never be forgotten—not even for a moment. The team repeated many additional simulations so that when faced with a critical event, such as the one that occurred in January 2015, the same mistakes would not happen again. Why NASA Trains The integrated simulation is the capstone training event for every flight controller. A flight controller must demonstrate technical expertise for his or her system before participating in a simulation. Yet, the simulation is where the flight controllers come together as a team. By performing simulations prior to the actual event, teams have been able to avoid numerous problems in space. Teams that had been drilled over and over again by the instructors were better able to handle a given problem, as was the case that early morning in January 2015. The team had practiced ammonia releases many times. What happened on the ISS that day was not a real ammonia leak, but rather a computer failure—one that had heretofore not been known as a possibility. The team had to figure out what was going on. However, the most critical actions—to save the crew and vehicle—were virtually reflexive. While the flight controllers and the flight director often lay awake at night hoping such a day will never come, they know that if it does, they will be prepared.