50 years ago: Splashdown day

Apollo 13’s damaged Service Module, as seen after it was jettisoned prior to re-entry.

*

            Hang in there, it won’t be long, we’re told.  It’s now officially splashdown day, April 17, 1970.  We’re not sleeping, with heavy hours yet ahead.  Splashdown is set for 1:07 p.m. EST. 

            Hang in there it won’t be long.   We’re cold and tired, and Fred Haise is feverish with a bladder infection.  At 3:35 a.m. EST, Capcom Jack Lousma radios, “We’ve found a way for you to keep warm.  We’ve decided to start powering you up now.”

            “Sounds good.” That’s earlier than planned.  We are a bit incredulous — and cautious. “And you’re sure we have plenty of electrical power to do this?”

            “That’s affirmative.”  Indeed, the Aquarius has twice the power and coolant water needed.

            Soon we can report, “It’s getting a little warmer in here.”

            Shortly before 6 a.m., Jack Swigert enters the Command Module.  One of his first tasks, he wiped the condensation off the dials and displays on the control panel.  He begins drawing power from the Lunar Module to warm some of the electronics and de-ice the thrusters.  When power flowed through Main Bus B, the one that first failed during the accident, he feels relieved — the bus  is undamaged. He charged the module’s re-entry batteries using Bus B.

            Hang in there, it won’t be long.  At 6 a.m. EST, we are 55,000 miles from earth and accelerating towards home.  But for some puzzling reason, our trajectory continues to shallow out.  We’re bumping outside the narrow corridor we need to thread for a successful re-entry.  We’re going to need to make a small maneuver, using the LM’s Reaction Control System, to nudge us back into the center of the corridor.  

            We’re damn tired, oozing fatigue from our fingers.  And making mistakes.  Instead of calling up the program for an RCS burn, we punch in the one for firing the big DPS engine.  Houston catches our mistake. 

            Shortly before 8 a.m. EST, we fire the RCS engines for 21 seconds.  After, Houston reports, “Good show, Aquarius.  You’re good right where you are.”

            “If you’re happy, we’ll maneuver to the Service Module sep[aration] attitude now.”

            Like much on this mission, our separations from the dead Service Module and the Lunar Module have never been done, never envisioned.  We need to keep the LM until the last, so the Service Module will be the first to go, pushed by the LM thrusters — then we’ll immediate reverse away. And try to get a good look at that module.

            We hit the jets, and yell up to the Command Module, “Fire.”  And Jack Swigert hit’s the “CM SEP” switch.   We back away and, cameras in hand, rubberneck the windows.  

            There it is. And what a sight.  “Man, that’s unbelievable.” 

            “OK, I’ve got her, Houston.  There’s one whole side of that spacecraft missing.”

            “Is that right.”

            “Right by the high-gain antenna, the whole panel is blown out, almost from the base to the engine. . . .Looks like a lot of — a lot of debris is just hanging out the side near the S-Band antenna.”

            We’re flying the strangest combination ever, just the Command Module nosed to the Lunar Module. he main work of power-up the Odysseybegins with a switch to the batteries, 2.5 hours prior to splashdown. “We’re starting now.” One by one, systems are switched on, carefully so as not to overload the batteries.  And one by one, layer by layer, right down the line on time, we resuscitate the command ship.  Odyssey awakens, as alive as if it hadn’t never fallen into a coma.

            One hour and fifty minutes after the main power-up sequence began, it’s time to jettison our LM lifeboat.  Jim Lovell, alone in Aquariusamid bags of refuse to be discarded, makes one last attitude maneuver, setting the craft so that is will be cast off to the side of the flight path, out of the way.  “OK, Houston, Aquarius.  I’m at the LM sep. attitude, and I’m planning to bail out.”

            Lunar Modules normally are jettisoned by using the Service Module’s thrusters to back away. The Service Module, of course, is gone. So we leave some air pressure in the tunnel between the two spacecraft and, releasing the docking latches, use the pressure to pop the LM away.

            Now just 1 hr. 10 min. before we hit the atmosphere, Houston calls, “Odyssey, Houston. We just had a formal go for LM jett. at your convenience.”

            We call, “Ten seconds.”

            “Five Seconds.”

            “LM Jettison.” We snap photos of our departed live-saving ship, and Houston calls, “Farewell, Aquarius, and we thank you.”

            “She sure was a good ship.”

            Our flight path has continued to shallow.  On the ground, they’re concerned.  Then mysteriously, just in time, the deviation stops increasing.  After the flight, engineers figure out the cause — a slight thrust from the evaporation of the water used as coolant by the LM. Normally, on the short hop to the lunar surface, it is not significant.  On a long voyage home, it is.

            Houston calls, “You’re looking good.  We’re really happy with the trajectory.”

            We’re approaching the moment of E.I — entry interface — where we will touch the skin of the thin upper atmosphere.  Unknowns remain.  Has the heat shield been damaged?  Will the pyrotechnics needed to deploy the parachutes work after the long cold soak?  We give some final words:  “I know all of us here want to thank all you guys down there for the very find job you did.”

            And we enter the blackout.  The silence is scheduled to last 3 min. 5 sec. before we emerge from the fires.

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