That attaches the liquid oxygen feedline to External Tank-119 being used to launch space shuttle mission STS-121.

A piece of insulation was liberated from a strut that attaches the liquid oxygen feedline to External Tank-119, being used to launch space shuttle mission STS-121. This piece of foam, weighing approximately 0.0057 pounds, is three inches long and one-eighth to one-quarter inch wide and was recovered by the Ice Team from the mobile launch platform at Pad 39B. It is believed that the rain experienced during yesterday’s launch attempt of Discovery caused water to run down the feedline and form ice near the strut next to the feedline bracket. As the tank warmed and expanded, the ice that formed most likely pinched the foam on the top of the strut, causing a crack and eventual loss of the small piece of foam. Photo credit: NASA