CAPE CANAVERAL, Florida – Spacewalking astronauts relied on brute force to remove a baulky ammonia line from a broken pump, overcoming a hurdle that bogged down their previous effort to restore full cooling to the International Space Station.It was the second spacewalk in five days for Douglas Wheelock and Tracy Caldwell Dyson. This time, to everyone’s relief, there was no burst of ammonia from the jammed connector, just a few frozen flakes of the toxic stuff that leaked out.The space station has been operating with only half its usual cooling capability ever since an ammonia coolant pump failed 1 1/2 weeks ago. Science research is on hold and unnecessary equipment is off until the pump can be replaced (AP)
