81 DAY IN THE LIFE: THE MAKING OF A MISSION CHAPTER 4 Figure 16. The final overview timeline used to execute the 20A mission. Shuttle missions went by Flight Days with the first beginning at the moment of launch, even if the astronauts had been awake for a while. Twenty-four hours later, Flight Day 2 would begin, and so on. This graphic illustrates the major events that the Shuttle and ISS crews performed. Other key activities—just as “N3 ground act” (approximately 04:00 GMT on Flight Day 07), which was performed by the ground—appear above the Flight Day events. Note that the flight control team and the astronauts followed a much more detailed timeline as shown in Chapter 1, but this provides a quick view of the key events and how they relate to each other.