Two astronauts cut short their spacewalk and hurried back to the safety of the international space station on Wednesday after a suit problem resulted in rising carbon dioxide levels for one of the men. NASA officials stressed that spacewalker Christopher Cassidy was never in any danger and experienced no symptoms of carbon dioxide buildup. Mission Control notified the crew five hours into the spacewalk that the canister for removing carbon dioxide from Cassidy's suit did not seem to be working properly. Flight controllers wanted him back inside quickly. Their battery replacement work outside the space station was left unfinished. Only two of four new batteries ended up being installed.
