Bursch and Walz prebreathe OPS for EVA 3 in the Quest Airlock, Expedition Four

ISS004-E-8037 (20 February 2002) --- Astronauts Carl E. Walz (left) and Daniel W. Bursch, Expedition Four flight engineers, undergo a pressure check in Quest's Equipment Lock, prior to the beginning of what turned out to be a five-hour, 47-minute session of extravehicular activity (EVA). The image was recorded with a digital still camera.