xix Each assembly mission flown by the Space Shuttle generally had two designations. First was the mission designation. For shuttle flights, this would be the Space Transportation System (STS) number such as STS-88, which indicated the 88th shuttle mission. Every ISS assembly mission would then have an assembly identification consisting of the numerical position in the planned sequence followed by the country of origin. US missions were denoted with an “A,” whereas “R” indicated Russian launches. Thus, the first US assembly mission is commonly noted as STS-88/ISS-2A, indicating it was the second American flight. One exception was the launch of the Functional Cargo Block, which was funded by the US but built, launched, and operated by Russia. This mission was designated 1 A/R, where the “A/R” indicates the joint nature of it. Sometimes, flights were added to the original plan. These were denoted by a decimal number such as 12A.1. When the order of flights were changed, as happened following the Columbia accident, the sequence was not renumbered. For example, flight 10A was moved after 13A.1. Table 2 lists all the assembly missions through 2016, plus several planned ones for future Russian modules. Note that assembly also required a number of EVAs. Those that occurred during a shuttle mission where simply numbered 1, 2, 3, etc. during that mission. Stage EVAs—those that occurred outside of shuttle flights— were numbered sequentially (1, 2, 3, etc.), with the prefix of R or US for Russian or USOS, respectively. As of 2017, there had been more than 80 USOS and Russian Segment EVAs to assemble and maintain the space station. More details can be found in Chapters 17 through 19. Crews (which generally consist of three people) to the ISS are called expeditions, and are also known as increments. Since the first, Expedition 1, was launched to the ISS in 2000, the station has been continuously inhabited. The first crew flew to the ISS on board a Soyuz but came home on the Space Shuttle Discovery, which also delivered the second expedition crew to the ISS on STS-102/ISS-5A.1. During early ISS operations, most increment crews flew to and from the ISS on shuttle flights as shuttle- rotating expedition crew members, or “ShRECs.” Separate crews visited the ISS to rotate the Soyuz rescue vehicles when they reached their 6-month on-orbit expiration date. After the loss of Columbia orbiter and her crew in 2003, Increments 7 through 10 consisted of only two crew members—one Russian and one American—who flew to and from the ISS on the Russian Soyuz. Since then, most crew members have flown on the Soyuz. In 2009, the ISS was sufficiently mature to support six crew members permanently. Until the Commercial Crew Program provides crew rotation services, all crews rotate to and from the ISS in the three-crew Soyuz. The Soyuz stays docked at the Russian Segment for the duration of the expedition in case an emergency forces the crew to evacuate. Half of the expedition crew members are Russian cosmonauts and the other half are made up of NASA and international partner astronauts, whereas the position of commander is rotated between the cosmonauts and astronauts. Crews consist of personnel from multiple countries and were selected, especially in the early days, to ensure that there would be at least one American and one Russian on the ISS at all times. Astronauts from ESA, CSA, and JAXA now routinely fly to the outpost and have also served as commanders. The other crew members on an expedition are referred to as flight engineers, designated generically as FE 1, FE 2, etc. These designations are used so that generic planning can occur even prior to a crew being selected or if crew members are swapped for whatever reason. The ISS changed considerably, and sometimes dramatically, through the construction phase of the assembly process. Operational products such as flight rules (described below) and procedures executed by the crew or ground differed as well, depending on hardware and software capabilities or available modules that changed after a given shuttle assembly mission. Thus, the increment was also subdivided into stages, one stage beginning at the launch of a shuttle flight and lasting until the next launch. All operations products such as procedures referenced this stage. A list of all the assembly missions is found in Table 2. Generally, construction occurred by attaching new modules and segments of the truss. However, modules or structures sometimes had to be moved from a temporary position to a final installation location. For example, P6 was the first set of USOS solar