50 years ago: Apollo 13 takes flight

Seemingly perfect . . .

*

            It’s April 11th. It’s 1970.  The fury and flood of activity to replace our Command Module pilot is over.  We are a team, about to leave earth for the third landing on the moon.  Who cares if fewer people are watching, that few will remember the fifth and sixth humans to walk on the lunar surface.  We’re about to head for the lunar highlands of Fra Mauro, a rough area that makes the landing more demanding that for Apollo 11 or 12.  We are expanding Apollo’s reach, opening up the lunar frontier.  Hence, our motto, “Ex Luna, Scientia.”  From the Moon, knowledge.  We are Apollo 13.

            As our liftoff time of 2:13 p.m. EST approaches, the launch test conductor calls, “Good luck, head for the hills.”  

            Liftoff, on time.  Houston calls, “Trajectory is good.”  

            Staging, that violent train wreck when we cut loose the first stage.  And we’re on the five J-2 engines of the second stage. “Guidance is good,” Houston calls.   At five minutes, they call, “You’re looking perfect.”

            But 30 seconds later, perfection ends.  We feel a shutter The center (inboard) engine of the second stage, programmed to shutdown slightly prior to the others to reduce vibration, has shutdown 132 seconds early.   

            We call, “What’s the story on engine five?”

            Our story almost changes at this point.   The shutdown mimicked that which had occurred on the unmanned Apollo 6 in 1968, the second flight of the Saturn V.  The cause was traced to excessive “pogo,” up-and-down vibrations like that of a pogo stick.  The vibrations were caused by oscillations in the fuel lines, which were subsequently redesigned, but apparently not well enough. On Apollo 6, two engines shutdown. If that happens now, while we’ll be able to limp into earth orbit, we won’t be going to the moon.  Apollo 13 will become a bland footnote.  If the remaining engines hold, Houston quickly determines, we should have enough power to leave earth for the Moon.

            The capcom calls, “Looking good at 8 minutes.”

            The second stage fires for an extra 34 seconds.  We’re still not back on the planned plot line to orbit.  Third stage ignition.  It also needs to fire longer than planned.  And yet it must leave enough fuel to restart after two orbits and send us out of earth orbit.  It fires for an extra 9 seconds.  And that puts us on-the-nose in our proper earth orbit.  As the third stage carried a 50-second reserve of fuel, we have enough for TLI, Translunar Injection, on the second orbit.

            It’s taken us 12 min., 29.83 seconds to achieve earth orbit, rather than the usual 11 min. 45 sec.  We’ve made the longest climb to orbit in history, a record that will stand perhaps for all time (for comparison, the Space Shuttle will reach orbit after 8.5 minutes).

            Everything checks out. We’re back on the pre-flight timeline. TLI comes on the button at 2 hrs. 35 min. 46.3 sec.   As if the glitch had never happened.

            Our Commander, Jim Lovell, calls to the ground, “It looks good to be back up here again.”

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