Piers Sellers works with the cover for the trailing umbilical system reel assembly that will be installed on the International Space Station.

During a Crew Equipment Interface Test (CEIT) inside the Space Station Processing Facility at NASA's Kennedy Space Center, STS-121 Mission Specialist Piers Sellers works with the cover for the trailing umbilical system reel assembly that will be installed on the International Space Station during their mission. A CEIT provides hands-on experiences with equipment used on-orbit. Mission STS-121 is the second in the Return to Flight sequence and will carry on improvements that debuted during last year's STS-114 mission and build upon those tests. Launch is scheduled in July. Photo credit: NASA/Kim Shiflett