breaking news tonight. trouble on the international space station, nasa has found a problem with the cooling system. the six-person crew is not in danger at the moment, joining me now is cnn's john zarella on the phone. john, it is not the first time they have had to do repair work of this nature. but how big a threat is it potentially? could it get worse? >> well, probably not, piers, they do have it under control. they do have two of these cooling pumps on the international space station. one of them this morning stopped working suddenly, they were able to get it restarted again, but they're trouble shooting the issue. and the problem is that they're not able to provide enough cooling for the entire space station now because the one that has been restarted is not working at 100%. so they have had to shut down the noncritical systems in three of the modules on the station, the u.s. harmony, the european