Homer Ahr had been asleep for 15 minutes when he got a call from his boss at Johnson Space Center.
“All he said was, ‘Homer, get into mission control as fast as you can.’ I didn’t have an idea of why I was going in there,” he said.
“Within 30 minutes at most I knew that they were truly in a life or death situation,” said Ahr.
Earlier that evening, Apollo 13 astronaut Jack Swigert had brought NASA mission control to a standstill with the now famous statement, “Houston, we’ve had a problem.”
The Apollo 13 craft was more than 300,000 kilometers into its journey to the moon when an explosion ripped through the tiny capsule.
On that day in April 1970, with the vessel venting its precious supply of oxygen, NASA knew it had few options for getting the three astronauts on the stricken spacecraft home safely.
“From that realization on, all we did was do everything we could to get them back,” Ahr said.
“It’s sort of like being in the ER, you know? If you have to jam a needle into somebody’s chest to reactivate their heart, you just do it. You don’t think about what you’re doing. You just do it.”
One of the many pressing issues was how to mount a rescue without firing the engines on the damaged part of the craft. At Johnson Space Center in Houston, TX, mission control narrowed the options to a maneuver never attempted before. The survival of the astronauts now hinged on using the descent engines on the lunar lander to put the craft on a homeward trajectory.
Mission control had limited time to work out how to pull off the maneuver. Luckily, just months before the crew blasted off from Cape Canaveral, two programmers had written the software for mission control to calculate just such a move.
One of those programmers was the 22-year-old Ahr, just a year out of college and working for IBM as a maneuver-planning expert supporting NASA flight officers in mission control.