EXpedite the PRocessing of Experiments for Space Station (EXPRESS) Racks are multipurpose payload rack systems that store and support research aboard the International Space Station (ISS). The EXPRESS Racks can support science experiments in any discipline by providing structural interfaces, power, data, cooling, water, and other items needed to operate science experiments in space.Facility Manager(s)
Boeing, Huntsville, AL, United States
Marshall Space Flight Center, Huntsville, AL, United States
National Aeronautics and Space Administration (NASA)Expeditions Assigned
2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19/20,21/22,23/24,25/26,27/28,29/30,31/32,35/36Previous ISS Missions
With standardized hardware interfaces, the EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Rack enables quick, simple integration of multiple payloads aboard the International Space Station (ISS). The system is composed of elements that remain on the ISS and elements that travel back and forth between the ISS and Earth via various space vehicles. EXPRESS Rack facilities remain on orbit continually. Experiments are replaced on the EXPRESS rack as needed, remaining on the ISS for periods ranging from 3 months to several years, depending on the experiment's time requirements.
Payloads within any EXPRESS Rack facility can operate independently of one another, allowing for differences in temperature, power levels and schedules. These facilities provide stowage, power, data, command and control, video, water cooling, air cooling, vacuum exhaust, and nitrogen supplies to payloads. Each facility is housed in an International Standard Payload Rack (ISPR), a refrigerator-size container that acts as the facility’s exterior shell.
The EXPRESS Rack facilities are comprised of various subsystems that enable experiment operations. The Rack Interface Controller (RIC), EXPRESS Memory Unit (EMU), Payload Ethernet Hub/Bridge (PEHB), EXPRESS Laptop Computer (ELC), EXPRESS Rack Thermal System, and the Solid State Power Controller Module (SSPCM).
Each of the eight EXPRESS Rack facilities can each support ten small payloads resulting in a total capability to operate up to 80 experiments. Eight of the EXPRESS Rack positions are the size of a shuttle Middeck Locker with a carrying capacity of 72 lbs and an internal volume of 2 ft3. The remaining 2 positions are International Subrack Interface Standard (ISIS) drawers, which has a carrying capacity of 44 lbs and an internal volume of 1.3 ft3.
Experiments in these facilities may be directly controlled by the crew or remotely controlled by the Payload Rack Officer (PRO) on-duty at the Payload Operations and Integration Center (POIC) at Marshall Space Flight Center (MSFC) in Huntsville, Alabama. Linked by a computer to all payload racks aboard the Space Station, the PRO routinely checks rack integrity, temperature control and the proper working conditions of the experiments.
The ISS experiences tiny vibrations caused by crew exercise, onboard pumps and motors, and other everyday activities that can upset sensitive science experiments. The Active Rack Isolation System (ARIS), which is installed on EXPRESS Rack 2 and partially on EXPRESS Rack 3, absorbs vibration to isolate and attenuate disturbances. ARIS attenuates vibration at the rack by imparting reactive forces to the rack to counter sensed vibratory accelerations, reducing the disturbance to payloads within the rack.
The EXPRESS Racks schedule to the ISS is as follows:
Pelfrey JJ, Jordan LP. An EXPRESS Rack Overview and support for Microgravity Research on the International Space Station (ISS). 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV; 2008; Reno, NV.
Counts SM, Sledd A. EXPRESS Rack Capabilities and Lessons Learned. Conference and Exhibit on International Space Station Utilization; 2001; Cape Canaveral, FL.