Flight Day 7 / Space Shuttle STS-121

Astronauts Michael E. Fossum and Piers J. Sellers (partially out of frame),
STS-121 mission specialists; participate in the mission's second session
of extravehicular activity (EVA). During today's six-hour 47-minute spacewalk,
Sellers and Fossum restored the International Space Station's Mobile Transporter rail car
to full operation and delivered a spare pump module for the station's cooling system.

IMAGE DATA © NASA