On April 14th, 1970, three men went on what was supposed to be the third lunar mission, including a walk on the moon’s surface. Almost 56 minutes into the mission of Apollo 13, when the command craft was 210,000 miles from earth, the command center asked the astronauts to perform the daily “stir” of the oxygen tanks—which destratified the air in the tanks, making the pressure gauges read more accurately.

Ninety-five seconds later, the astronauts heard “a pretty large bang.” Twenty-four seconds later, Command Module Pilot Jack Swigert said, “Okay, Houston, we’ve had a problem.” A second and a half later, Mission Commander Jim Lovell chimed in, "Houston, we've had a problem. We've had a Main B Bus undervolt."

At first, Swigert thought that a meteoroid had hit the landing module. Lunar Module Commander Fred Haise was monitoring the power and saw that the fuel cells were low on voltage—which is to say, they were “undervolted.” The fuel cells that powered the ship, operating off a mixture of hydrogen and oxygen, were not producing enough electricity.

Minutes after the accident, the astronauts saw that of the two oxygen tanks, tank 2 was empty, and tank 1 was losing oxygen. Since the fuel cells required oxygen to power the ship, not to mention provide breathable air for the astronauts, they knew immediately that they were in big trouble.

The moon landing had to be scrapped. But with a limited supply of fuel and breathable air, the question remained about whether they could even return to earth before the astronauts suffocated or froze to death.

Initially, mission control in Houston thought about simply turning the ship around and returning to earth. But the problem with that idea was that using the thrusters to reverse course would deplete the remaining oxygen before the ship could splash down. Everyone agreed that the only way to return the astronauts safely was to allow the ship to continue toward the moon, go past it, and let the moon’s gravity slingshot the ship back around the moon in a giant horseshoe movement. They could then use the momentum caused by gravity to power their reentry into the earth’s atmosphere.

The urgent question was: would they have enough fuel and oxygen to last the four days it would take to complete?

The Lunar Module, or the landing module, had its own limited oxygen tanks and fuel cells. So mission control told the crew to transfer everything to the Lunar Module. Use it as a lifeboat of sorts.

The Lunar Module was designed for two people for 45 hours on the moon’s surface. But now, there would be three men for an even longer period. They remembered that they had some extra oxygen canisters in the main ship—so now they had plenty of oxygen.

But that raised a whole new problem. Because the Lunar Module was designed for two people, with three people, the CO2 would build up in the cabin faster than the filters could scrub it. They needed to add the filter from the main ship to handle the extra CO2 buildup. Unfortunately, the filter in the Command module was square; but the filter in the Lunar Module was round.

To filter out the excess CO2, they literally had to figure out how to fit a square peg into a round hole. Otherwise, the astronauts would run out of breathable air before touching down.

In the 1995 movie about Apollo 13, with Tom Hanks, Kevin Bacon, and Bill Paxton, directed by Ron Howard, there’s a frantic scene back down in Houston as they try to design a solution to the problem.

Engineers gather together in a room. The chief engineer takes a big box and dumps it on the table. He sorts through all the objects and picks up the square filter in one hand and the round one in the other. He gestures to the scattered parts on the table and says, “We’ve got to make this fit into that using only this.”

But it’s the “only this” I find so fascinating. The box contains only items the astronauts have at their disposal. No sense dreaming up a solution that requires somebody to make a quick trip to AutoZone to pick up parts and one of those pine tree air fresheners.

In other words, they’ve got to engineer a solution—not out of parts they wish they had, but only out of parts they actually had.

Did you ever do that? Spend all your time grousing about what you don't have?

If only you just had that one thing … everything would be perfect.

But would it be? I mean, ever really perfect?

I don't know. Maybe it would be. But more often than not—at least in my case—pining for what I don't have is a convenient way to avoid using what I do have. To do what I know I need to do.

The flooring guys who were supposed to install the quarter-round molding for me after laying the floor … laid the floor and never came back.