Apollo 13 had experienced an oxygen tank explosion that had crippled the Service Module, leaving the Apollo 13 crew stranded in the Lunar Module (LM, formerly called LEM), which was connected to the Command Module. The even bigger problem? How much pressure would be necessary to safely separate the modules and get the three stranded astronauts home.
40 years later the UTIAS team, Professors Barry French, Phil Sullivan, Rod Tennyson, Irvine Glass and Ben Etkin were honored during a ceremony at The Canadian Air and Space Museum for providing NASA with the exact calculations needed to bring the Apollo 13 crew home safely. We asked Professors Barry French and Phil Sullivan to share some of their memories about that famous day.
the newsmagazine: How did the U of T Scientists get involved in Apollo 13? Why did Grumman Aerospace contact you?
Phil Sullivan: Having obtained research support from various US government agencies, UTIAS already had a strong reputation in the USA. In particular Dr. French’s highly sensitive quadrupole mass spectrometer for trace gas analysis had been used on a NASA mission to Mars, as I recall. I think his involvement with US space programs was thus well known to senior personnel at Grumman, the builders of the LEM.
tn: With only four hours to help, what resources did you use to calculate the correct pressure? Would you use the same resources today?
PS: Basically, classic “back-of-the envelope” estimates using engineering judgements based on past experience, Newton’s three laws of mechanics, and some known scaling laws for the propagation of blast waves. Data on masses and the like was supplied by Grumman, and physical constants were obtained from readily available text books. I used a slide rule to “crunch the numbers.” Given such a short time to respond, the approach today would be basically the same, except for possibly using the internet in place of text-books for rapid access to physical constants, as well as a hand calculator in place of a slide rule.
tn: As the story goes, UTIAS was in the middle of a routine staff meeting when the phone call from Grumman came through. What was that moment like? Can you recall the thoughts going through your mind?
Barry French: I left the meeting to take the call... I was a bit overwhelmed but we instantly and unanimously agreed to help all we could.
PS: I expect most of us thought that Apollo 13 was “game over” for the astronauts. I can distinctly remember hoping that some one else was doing similar calcs, and was surprised to learn later that we were the only ones. I suspect that the engineering teams involved at NASA and elsewhere had judged that the proposed separation solution would work, but because of the huge risks involved, wanted an independent opinion.
tn: How has the Apollo 13 incident influenced your career and/or life?
BF: It was an immensely gratifying experience to have participated in such a high profile event and in helping to save four human lives. And my grandchildren love the story (and all this unexpected publicity 40 years later).
PS: In later years I used it in lectures to engineering students as an illustration of “engineering at work” validating some of the material we teach, and as an example in a philosophy of science text to refute the postmodernist claptrap that passes for serious critiques of science in certain disciplines.