Today marks the 35th anniversary of the near fatal
explosion on NASA’s Apollo 13 mission to the moon. At the
same time it was NASA’s worst and finest moments. The story
behind the story is that Apollo 13 made it home, due in large
part, to a simulation done a year before the explosion for Apollo 10.
As part of training, the flight teams go through various
scenarios. Each scenario is carefully scripted and is
intended to prepare everyone for possible problems. The fear
is that if you come across something you haven’t prepared
for, you may perish because you don’t have the time or you do
something that irreversibly leads to your death.
Such was the case in a simulation for Apollo 10 much like
what eventually happened. A flight simulation in which the
fuel cells failed, at about the same point in the mission as
actually occurred, resulted in the simulated deaths of the
astronauts because they didn’t have procedures required to
power the various systems (and didn’t have the time to
come up with them in real time before running out of
However, even though the simulation indicated developing
such procedures were critical to the crews survival, NASA
decided the possibility of losing the fuel cells was
unrealistic and therefore did not order such procedures to be
Fortunately, for the Apollo 13 crew, James Hannigan, the
Lunar Module branch chief felt otherwise. He ordered his
deputy, Donald Puddy, to form a team to come up with a set of
procedures that would work. Just in case. Critical to the
procedure, that the team came up with was the idea of
reversing the power flow, via umbilical cables, from the
Lunar Module back into the Command Module to provide the
current required to re-start all the systems.
It is doubtful that the crew would have survived the
actual emergency had not these procedures been developed
before hand and solutions found for problems that just could
not be solved in real time.
You can read the fascinating account of human systems
dealing with mechanical and electrical systems from the
Institute of Electrical and Electronics Engineers article,
here. It was indeed, their finest hour.