Robotic arm operators aboard the International Space Station installed the Express Logistics Carrier (ELC) 2 on the station’s Starboard 3 truss, or backbone. The carrier measures about 16 feet by 14 feet and contains 9900 pounds of spare equipment for the station, including a control moment gyroscope, a pump module, a high pressure gas tank, a cargo transport container that holds 10 remote power control modules, and a reel assembly for the station’s mobile transporter. It joins ELC 1, installed earlier in the mission on the Port truss. ELC 4 will launch on space shuttle Endeavour’s STS-134 mission in July 2010 and ELC 3 will launch on Discovery’s STS-133 mission in September 2010. The carriers store spare hardware that is easily accessible be station crew members for any future repairs and will increase the longevity of the station.