Each platform is made from steel[citation needed] and serves as an external pallet that can hold spare parts, also known as orbital replacement units (ORUs), for the space station.The first of the external stowage platforms, called ESP-1, was installed on the port side trunnion pin on the outer hull of the Destiny Laboratory Module on March 13, 2001 during the second EVA of the STS-102 Space Shuttle mission.ESP-1 holds the following ORUs:[3] ESP-2 was detached from its Keel Yoke Assembly (which remained in the Orbiter) and installed with the assistance of Space Shuttle Discovery's robotic arm and two spacewalkers during the STS-114 mission.The ORUs on ESP-2 are: Notes: ESP-3 was detached from its Keel Yoke Assembly (which remained in the Orbiter) and installed on the P3 Truss at UCCAS-1 on August 14, 2007 during the Space Shuttle STS-118 mission.It has seven attachment sites for ISS spare parts and assemblies, called Orbital Replacement Units (ORUs).
FRAM breakdown
Location of ESPs on the International Space Station
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