CHAPTER 6 DAY IN THE LIFE: “BRAIN TRANSPLANTS” ON THE INTERNATIONAL SPACE STATION 114 operating during that vehicle’s mission to the ISS. However, both the visiting vehicle and the software transition schedules are often very dynamic. If a visiting vehicle mission was to overlap a software transition, its software would need to be tested with both versions of ISS software. Flexibility could be provided by testing all permutations of software interaction. However, the required testing is time consuming and expensive, thus a lot of effort is put into scheduling software transitions away from visiting vehicle and other dynamic operations. To date, this has not been anything more than a planning exercise. Therefore, careful evaluation of impacts to the software schedule are required when a mission does change its schedule. “EPIC or BUST” Don Pettit, Expedition 30 and 31 An orbital “brain transplant” can be done with new software uplinked into the flight computers via radio waves. As in a B-grade sci-fi movie where some hapless creature’s brain is reprogrammed, the old system is replaced with the new—usually, but not always, with known results. This is accomplished from Mission Control. If the brain transplant goes as designed, the on-orbit crew may not even know it happened. Sometimes, the necessary upgrade actually requires new brains. This happened during my last visit to the space station in 2012 during Expedition 30. The central processing units for the main computers were being upgraded from the 8086/16 MHz processors that were launched with new Pentium 266/144 MHz chips (Chapter 5). These new brains, known as Enhanced Processor and Integrated Communication Controller, or EPIC, cards, were required to handle the more advanced software before the visiting cargo spacecraft could approach and berth to the United States On-orbit Segment—events planned for the very first time about a month into our mission. No pressure on us, except that the fate of the commercial space program hinged on our ability to perform this brain transplant. My commander Dan Burbank and I received hours of preflight training, prying the old computer boards from the MDM out from practice flight computers and replacing them with shiny new ones, complete with gold-plated contacts and conformal-coated circuits. The conformal coating is a polymeric film that keeps aimlessly floating bits—i.e., little chunks of zero-gravity detritus—from shorting out the circuit boards. All the brain transplants were planned early in our mission so that the first commercial spacecraft, Space Exploration Technologies Corporation (SpaceX) Dragon D1, could pay us a visit. The new brains, all 10 of them, were already on orbit well before my launch. We were all set for brain surgery. Or so we thought. Figure 2. Astronaut Don Pettit uses the oscilloscope to measure the EPIC cards’ timing signals. Then we found out the new processor cards (already on orbit) were built at the factory with a defective component that would cause the internal clock timing to go bonkers, thus causing the computer to do the orbital equivalent of the “blue screen of death.” It is not good for spacecraft brains to go into la-la land when you are traveling at 28,163 km/h (17,500 mph) with a commercial spacecraft waiting on your doorstep (Chapter 14). To complicate Several program reviews are scheduled as the time approaches to ensure everything is ready for the transition. As with other major activities, the flight director will brief the program management on the proposed changes and plan, with the final “go/no go” occurring at the ISS Mission Management Team level a few days before the planned event. Here, the program