Staying the course home

Apollo 13’s Jack Swigert with the improvised air purifier.


            It’s getting cold upstairs, in the Command Module, our “bedroom,” about 40 degrees. “It’s not uncomfortable at all in Aquarius, but it definitely is cold in Odyssey.”  Yet if you don’t move, your body heat provides a bubble of warmth, as there are no convection currents in weightlessness to draw the heat away. 

            At 8:38 a.m. EST, we are 38,894 mi. from the moon and 208,027 mi. from Earth, the point, the ground informs us, that we pass into the Earth’s sphere of influence and begin accelerating toward it.  Jack Swigert replies, “I thought it was about time we crossed.  Thank you.  We’re on our way back home.”

            We appear in good shape in the near-dormant Lunar Module, Aquarius, only the environmental control system and radio switched on.  They pull only a bit more than 12 amps.  We’re maintaining good power reserves.  Indeed, it now appears that we’ll have 500 amperes left for reentry on the 17th. And water enough to last 17 hours beyond splashdown.  We’re fat on oxygen, with enough for 86 hours beyond splashdown.  

            We do have one problem to contend with.  Carbon dioxide, a byproduct of our breathing, is building up.  Lithium hydroxide in round canisters is used to scrub the carbon dioxide from the air.  But the canisters, designed to support two men for two days, are saturated.  The Command Module carries a supply of canisters for its (now inactive) system.  Wouldn’t you know it, those canisters are square.

            The ground reads up a procedure to adapt them to the LM system.  It sounds like a Rube Goldberg home repair.  We use duct take, a plastic bag, a piece of cardboard to wrap the box-like canister, plug an unneeded outlet with a sock, use an oxygen hose to attach it to the LM system.

            And the damn thing works!

            Yes, we appear in good shape.  Except for one thing:  For some unknown reason, our trajectory is shallowing out.  We’ll miss the earth by about a hundred miles.  Mission Control plans a course correction for late evening, a 14-second blip by Aquarius’s main engine.  However, our navigation system is shut down.  How will we orient the spacecraft?

            Everything will be done manually.  First, Jim Lovell will orient the spacecraft so that the sun is in the LM’s small overhead window.  Then rotate so that the crescent Earth is pinned in the forward-facing windows. It’ll take two of us to keep the spacecraft in position, working the two hand controllers.  Jack Swigert will use a stopwatch to time the burn.

            At 11:31 p.m. EST, we’ve got Aquarius in position.  Ignition . . . and Shutdown.  The brief burn only changes our velocity by 5 mph.  That’s enough to pull us back into the reentry corridor.

            Now if everything just hangs together — one more full day in space ahead.  And no one is sleeping very much.

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