It's the evening of April 13th, 1970, 200,000 miles from Earth and two days into Apollo 13's mission to land on the moon.

Inside the spacecraft, Jack Swigert, a square-jawed astronaut from Colorado,

flows through zero gravity to the main control panel. The other two members of the crew,

lunar module pilot Fred Hayes, and Commander Jim Lovell, are busy packing away equipment.

But there's a routine task mission control wants Jack to complete. The spacecraft is equipped with vital hydrogen and oxygen tanks that help power the systems

on board and provide air for the astronauts to breathe.

But in the deep cold of space, these tanks require regular stirring, so they're equipped

with fans to churn up their contents.

Now Mission Control wants Jack to turn on one of these fans,

so he reaches over to a panel and flicks the necessary switches.

Then Jack waits a few moments for the fans to do their work

before switching them off again.

But then, from somewhere behind him in the spacecraft,

Jack hears a loud, dull thumb.

The spacecraft shudders, and Jack glances back at his commander, Jim Lovell.

They both had the same thought.

This must be a joke, and stare daggers at the third crewman Fred,

who's been playing tricks on them ever since they left Earth's orbit.

But Fred looks back, nervously.

Whatever the noise was, he had nothing

to do with it. Then the master alarm goes off, a warning that something serious is wrong with the

spacecraft. As the other two astronauts hurry to the control panel, Jack's eyes flash across the

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