277 DAY IN THE LIFE: IN-FLIGHT MAINTENANCE CHAPTER 16 The Mod Kit Short for “modification kit,” a mod kit is a collection of equipment that needs to be installed on the ISS (usually inside, but sometimes outside, as well) to accommodate new hardware or new functions on the spacecraft. Mod kits can be small in size, or they can be quite large and complex. The need to install a mod kit usually presents a relatively rare opportunity to renovate and/or remodel the space station. Installation of a mod kit often requires the use of the many different maintenance techniques mentioned in this chapter. An example of a relatively small mod kit was the transition away from a large, single ORU in the urine processor that both filtered and stored pretreated urine. The large, single tank was being disposed of when the urine container was at its end of life, even though the filters (which were contained inside the tank) still had a much longer life available. The mod kit replaced this single component with a number of smaller, individual filters and a separate urine containment tank. The new design allowed for each subcomponent to be used until it had reached its own end of life. The mod kit contained the various separate filters, urine tank, and hoses to connect them all together. In this case, the OSO flight controller’s job was to determine how to best install the new hardware to make sure it would all fit inside the rack that was designed and built to accommodate the single, larger ORU. An example of a much larger mod kit is the project to reconfigure the ISS to support the Commercial Crew Program. This renovation requires the relocation of the Permanent Multipurpose Module and PMA3 module, installation of new docking adapters and control panels to operate them, and installation of new equipment so the ISS can communicate with the new commercial crew vehicles. New power and data lines will run throughout the US Segment to connect the new hardware, and to ensure full functionality of the modules that were relocated. A number of software changes on the ISS are also required to ensure the ISS MDMs know how to communicate with and control the new and reconfigured equipment. A number of mod kits are involved in this US Segment reconfiguration. Planning and coordinating the implementation of this major rearrangement is being done across all of the flight control disciplines, the ISS Program, engineering organizations, and the various ISS Program contractors. The mod kit components and hardware will not all arrive at the ISS at the same time. They will launch to the ISS over a span of a number of years. Thus, choreography of what can be installed or relocated is as important as developing the maintenance procedures to actually perform the work. The first mod kit installation on the ISS for this effort occurred in January 2015, and completion is expected in time to support the first docking of a commercial crew vehicle in 2018. This major renovation work is also choreographed to ensure that the ISS and its crew can remain focused on the primary ISS mission of performing as much research and scientific investigation as possible. Conclusion Maintenance is a key factor in keeping the space station fully functional to support not only the life and livelihood of its crew but also its primary mission of unique off-Earth scientific research. Maintenance comes in a wide variety of forms, from simple cleaning and hardware replacement to intricate diagnostics and component repair. Repairs have proven successful through prepositioning supplies, detailed pre-launch training, and teamwork between the ground and crew. Often, adaptability and ingenuity has been required for problems that were not always anticipated. A copious supply of tape and resourcefulness from all involved has also proven to be a key factor, and will undoubtedly remain so for the rest of the space station program.