BIO-Plex, or Bioregenerative Life Support Research Complex, was developed to continue the integrated, human-in-the-loop tests under way at the Johnson Space Center in developing and refining sustainable, bioregenerative systems for crew life support during a long-duration surface mission such as the 425-day portion of the Mars DRM.
Comprised of several 4.25-m diameter hard modules similar to the ISS US Operating Segment standard module in a horizontal position joined by a central tunnel, the complex would eventually house two chambers for "biomass production" of edible plants, one laboratory chamber, one mechanical module, an airlock and one habitation chamber to accommodate four crewpersons on stays up to 425 days.
Because the program for the habitation module was not yet established, and because the systems to be integrated in this facility are also expected to change considerably over the lifetime of the facility, utility lines were placed in areas of least negative impact with room to grow.
Studies were done to determine which parts of the interior cylindrical volume would be least usable by the crew; then, integrated utility chases were built to fill in those volumes and carry all necessary systems--air, power, coolant, data, water--to all usable parts of the facility. Then, a standard outfitting module of 45cm or 90cm width was developed to permit reconfiguration of the interior elements between tests, so that the work areas of the lab and the varied program of the habitation module could be tested against crew usability and productivity.
Finally, a number of variants were developed for the interior plan and downselected by a jury made up of astronauts and JSC space architects.