MONTREAL — High above the Earth, the lives of the Apollo 13 astronauts depended on a series of calculations by Canadian engineers. The slightest miscalculation could have meant death for the three-man crew.
“It carried the seeds of disaster if it went wrong,” says Ben Etkin, who was part of the University of Toronto Institute of Aerospace Studies team who helped rescue the astronauts 40 years ago.
The drama unfolded on April 13, 1970, when astronaut Jack Swigert sent one of the most famous messages in space travel history to ground controllers: “Houston, we’ve had a problem here.”
The words sparked a series of events that would grip the world for four days as people waited to see if the astronauts would safely navigate the more than 320,000 kilometres back to Earth.
Apollo 13 was attempting what was supposed to be the third manned landing on the moon before things went horribly wrong.
The mission had to be scrapped when an oxygen tank exploded, forcing NASA scientists and the astronauts — Swigert, Jim Lovell and Fred Haise — to scramble to get the crippled spacecraft back to Earth.
Food and water were limited on the spacecraft. Sleep was impossible because turning off power caused the temperature aboard the craft to plummet.
One phone call for assistance was made to the University of Toronto Institute of Aerospace Studies on April 16, 1970.
“At the time, our thoughts were: ‘we’ve got to do the damned best we can because a lot is riding on it’,” Etkin, who is now 91, said in an interview with The Canadian Press.
The Apollo spacecraft had three components — the astronauts’ command module, a service module which provided life support and rocket thrust, and the lunar module, named Aquarius, which was slated to be jettisoned after the moon landing.
But when the explosion disabled the service module, Aquarius became a lifeboat for the astronauts as they headed home after circling the moon. The actual trip back would be done in the command module.
It was in the separation of the lunar and command modules that the Toronto team played a vital role.
Rockets that usually would have split the two vehicles were inoperable and it was decided to use pressure in the tunnel that connected the two units to perform the manoeuvre.
A ring of explosives located just 10 centimetres from the command module’s hatch would blow away the tunnel connecting the lunar module and the re-entry command module.
“That short tunnel had air in it that was pressurized and when the ring of explosives was set off, the two parts of the returning spacecraft would be pushed apart by the pressure in that tunnel,” Etkin said.
The University of Toronto team was asked to figure out exactly how much pressure was needed to separate the two modules.
“If the pressure was too low, the two parts of the spacecraft would not be pushed apart with sufficient speed,” Etkin noted.
“Above a certain pressure, the shock wave caused by the explosive could damage the entry hatch to the re-entry module.”
Etkin said if the hatch had been damaged it could have meant death for the astronauts during their return.
“During the approach, if the hatch was damaged and they lost air pressure inside the compartment due to leakage through that hatch, it would have been game over,” he said.
Dr. Bill Carpentier, a retired NASA flight physician, was in the mission control room when Swigert informed ground controllers in Houston there was a problem.
The 74-year-old Canadian-born doctor, who was monitoring the astronauts, says it became immediately clear the problem was with oxygen levels inside the command module.
“As soon as they knew they had a problem you could see on the electrocardiograms their heart rate went up considerably, and their respiration rate went up,” the B.C. native said in an interview.
Carpentier, who now lives in Belton, Texas, says the most tense moments came during the re-entry into the Earth’s atmosphere when there’s usually a communications blackout.
“The blackout period was longer than usual and that made everybody very anxious,” he recalled.
“When, finally they had communications with the spacecraft, they were on the right glide path to come in and you knew they were going to make it.”
Forty years later, the Canadian Air and Space Museum is making sure the critical contribution made by the University of Toronto team does not slip by unnoticed.
Several team members will be at the museum near Toronto on Tuesday to receive the Pioneer award to highlight their role in the Apollo 13 rescue.
NASA classed the mission as a “successful failure” because of the lessons learned in rescuing the three crew members from the far reaches of outer space.
Barry French, another member of the University of Toronto team, said his group only found out later there was a happy ending to the Apollo mission.
“We all went to bed that night and didn’t know what the situation was,” the 78-year-old said in an interview from Toronto.
“In the morning when we woke up, we heard they landed safely.”