 ELCs are exposed pellets installed on the outboard truss of the ISS intended to support vacuum capable payloads such as scientific experiments built for operations on the outside of the station or for holding spare parts.Bresnik participated in the second and third EVA of STS-129.On 21 November 2009 Bresnik stepped outside the station with veteran spacewalk Michael Foreman, the two spent six hours and eight minutes outside of the ISS installing a piece of equipment called the Grappling Adapter to On-Orbit Railing (GATOR) on the European Columbus, installing a wireless video system on the outside of the station and setting up a cargo attachment system.