Cooling Issue News Today : Breaking News, Live Updates & Top Stories | Vimarsana

the mission's ambitious agenda remains landing the first woman and first person of color on the moon. this by 2025. also going further afield, ultimately getting humans to land on the surface of mars. but before we get there, "artemis 1" will need to fly around the moon using the most powerful rocket to launch since "saturn 5" took astronauts to the moon for the last time back in 1972. space and defense correspondent kristin fisher is live from kennedy space center. you are ready to see it take off like we all were, so tell us what -- what the final issue really was here that led to ...

"For the second time in 15 days an AC local train has departed the station with doors open. No AC and Ventilation in the train. No one attending complaints by passengers," tweeted a passenger.

Orbiting international space station. >> failure of an internal flow control valve. >> reporter: to american astronauts are venturing out. their mission? to replace a pump needed to cool the vessel. >> i don't know if you guys believe in miracles, but i got the hitch pin on the first try. >> that's awesome, rick. >> reporter: offer the weekend, astronauts rick mastacchio and mike hop kins, cooling fluid, ammonia. >> hooking up the big heavy ammonia lines are massive. if you were to leak ammonia, not a very pleasant chemical. you couldn't bring it inside. there's definite risk out there. >> rep...

>> over the weekend, astronauts rick mastracchio and michael hopkins removed the faulty cooling pump, which is the size of a refrigerator. any now must install the new one. their task is a delicate one. the equipment contains a knoxious cooling fluid, ammonia. >> some of the danger is hooking up the big heavy an money yag lines, they're thick and massive. hooking those up if you were to leak ammonia, it's not a pleasant chemical. you couldn't bring it inside. there's definite risks out there. >> mastracchio will be wearing a newly tailored space suit on today's mission, a replacement after a c...

Mastracchio's space suit which had a cooling issue. nasa says he was never in any danger. now saturday's spacewalk lasted more than five hours. it was billed as a success so far. this spacewalk has been going on for more than four hours. the hope is that they will be able to wrap things up and go back inside the international space station very soon and by the way, this is the second time ever there has been a spacewalk on christmas eve, the first one happened 14 years ago. >> thanks so much. certainly will be a christmas eve they don't forget. now we're joined by nick. how crucial is this ope...