HOUSTON, TX – It’s been more than forty years since Apollo 13’s storied journey. Still it’s a story that’s captured the imagination of generations of Americans. For those who were there, it’s a night that still lives in their memories. Perhaps no one’s more that Sy Liebergot’s.
“We had these little fans,” he says. “And the crew would turn on these little fans with four switches, stir the cryos for about a minute, shut them off. No big deal. Done it before. We’d already done it a couple of times on this mission; tank didn’t blow up.”
Liebergot was the flight controller on duty that night that radioed the crew of Apollo 13 and asked command module pilot Jack Swigert to stir the tanks.
“13 we’ve got one more item for you when you get a chance,” NASA’s recordings from that night say. “We’d like you to stir up your cryo tanks.”
“Okay, standby,” Swigert answers.
Then the message that’s become iconic of Apollo 13’s journey. “Okay Houston, we’ve had a problem here.”
Unbeknownst to anyone at NASA, faulty wiring within Apollo’s oxygen tanks had been laying-in-wait some 56 hours into the mission. The next time any one of the astronauts “stirred the tanks” there was going to be trouble.
“Read out on oxygen tank two when off-scale high,” Liebergot explains. “‘Ah, let’s stir it again, see if we can knock something loose.’ and it’s didn’t help, but the tank didn’t blow up, it only blew up when I asked for an extra stir before the crew went to sleep.”
In the end, it was a disaster that couldn’t have come at a better time, had flight controllers waited until the crew woke in the morning to stir the tanks, the explosion would have been even more disastrous and crew wouldn’t have made it home alive.
Liebergot spoke to students at the University of Houston about that night.
“It’s amazing. It’s actually unbelievable,” student Ryan Hannemann said.
And though he’s retired from NASA, he likes meeting with students talking about Apollo 13 and looking back on his team’s greatest accomplishments.
“We went to the moon; that’s what we did.”