For the first time, an experimental treatment made from human embryonic stem cells has shown evidence of helping someone, partly restoring sight to two people suffering from slowly progressing forms of blindness.CAPE CANAVERAL, Fla. – Astronauts in orbit and on the ground practiced Monday for a major repair job this week at the international space station, struck by a massive cooling system failure.
The weekend malfunction knocked out half of the space station’s cooling system, forcing the crew of six to turn off unnecessary equipment and halt scientific work to avoid overheating.
NASA’s space station program manager, Mike Suffredini, ranked the problem as one of the most serious in the 12-year history of the orbiting lab, but he stressed the outpost could keep going indefinitely given the current situation.
The fear is that the second cooling loop could shut down at any moment and leave the station in precarious shape.
For now, “everything the crew needs to survive, they’re in good shape, all those systems are active,” Suffredini told reporters Monday. “What we’re talking about, really, is it would be a significant challenge if we suffered the next failure.”
Two of the Americans on board – Douglas Wheelock and Tracy Caldwell Dyson – will venture out on a spacewalk to replace the pump Thursday. A second spacewalk will be needed to finish the job, probably Sunday.
The 780-pound pump is difficult to handle, and the astronauts will need to guard against any hazardous ammonia leaks.
Engineering teams have been working since the cooling loop shut down Saturday night. A pump that drives ammonia coolant through those lines failed when a circuit breaker tripped.
