“Okay,” said Kranz. “G.N.C., you want to look at it and see if you see any problems?” A hardware restart indicated some unusual event that the computer had detected and was checking. Then Lovell’s voice stopped Kranz short: “Houston, we’ve had a problem. We’ve had a Main B Bus undervolt.” An “undervolt” meant a substantial reduction of power into Bus B, jeopardizing the equipment running off it.
