Mission STS-118 - Flight Day 11

2007-08-18 - Flight Day 11 - Canadian Space Agency astronaut Dave Williams, STS-118 mission specialist, participates in the mission's fourth and final session of extravehicular activity as construction and maintenance continue on the International Space Station. During the 5-hour spacewalk, Williams and astronaut Clay Anderson (out of frame), Expedition 15 flight engineer, installed the External Wireless Instrumentation System antenna, attached a stand for the shuttle's robotic arm extension boom and retrieved the two Materials International Space Station Experiments (MISSE) to be brought back on the shuttle. (Credit: NASA)