There are currently 18 EXPRESS Rack facilities installed on the International Space Station. Each of these can accommodate ten (10) standard-sized small experiments, supplying them with power conversion and distribution, data and video distribution, nitrogen supply and exhaust distribution, and thermal control interfaces. The ExPRESS Rack concept provides the capability for a simple and shortened integration template.
Approximately 50% of the EXPRESS payload accommodation capability (~ 30 payload locations) is available for International Space Station’s U.S. National Laboratory usage.
There are 7 EXPRESS Racks for primary payload accommodations capability.
EXPRESS Racks 1, 2, 3, 4, 5, 7 and 8 are used for primary payloads, Express Rack 6 is utilized to house the Crew Galley.
There are 5 facility class racks; Fluid Integrated Rack (FIR), Combustion Integrated Rack (CIR), Microgravity Science Glovebox (MSG), Materials Science Research Rack (MSRR) and Window Observational Research Facility (WORF).
There are 3 cold storage support racks; Minus Eighty-degree Laboratory Freezer for ISS (MELFI-1), MELFI-2 and MELFI-3.
There are 3 human research facility racks; Human Research Facility-1 (HRF-1), and HRF-2, and the Muscle Atrophy Research Exercise System (MARES).
The Glenn Research Center (GRC) operates fluid physics experiments in the FIR and combustion experiments in the CIR facilities. GRC operates several material science, fluid physics and combustion experiments in the MSG facility. Glenn Research Center also use EXPRESS Rack 1 for the Microgravity Acceleration Measurement System (MAMS) and the EXPRESS Rack 4 to operate the Space Acceleration Measurement System (SAMS).