The Watch That Helped Save Apollo 13 | Omega Speedmaster

The engine has to burn for about fifteen seconds. The computer is off. And three astronauts are trying to steer a damaged spacecraft back to Earth. Jim Lovell looks out the window to keep the planet in view. The men have been awake too long, the cabin is cold, and every remaining bit of power matters. Somewhere on board is a small, old-fashioned answer to one urgent question: when do we shut the engine off? The answer is a wristwatch. A mechanical chronograph. Jack Swigert has one on his wrist, and the Science Museum credits his watch with timing crucial engine firings during Apollo 13. How did a watch end up with a job on a trip to the Moon? And why would NASA trust it when the spacecraft itself was in trouble? In an Apollo photograph, almost everything looks specially built for space. The suit. The helmet. The spacecraft behind it. Then there is the watch: a dial, a couple of buttons, and a strap over the sleeve. is an Omega Speedmaster. A chronograph is a stopwatch you can wear. Press one button and a hand starts counting seconds. Press it again and it stops. That matters when a task must last a precise number of seconds: an experiment, a maneuver, a stretch outside the spacecraft.

The Speedmaster does not need the ship's electricity to do that job. You wind it by hand. The watch is not smarter than the spacecraft. It has one simple advantage: it keeps doing its job when another system has to be switched off. That was useful long before Apollo 13. But first the watch had to persuade NASA that it belonged there at all. Imagine buying a watch and asking the salesperson a few questions. Will it survive water? A hard knock? Magnetism? Now add violent acceleration and temperatures that would make an ordinary day feel very far away. That was the sort of list NASA brought to its search for a crew chronograph. NASA tested watches for precision and reliability.

The Speedmaster made the cut and was qualified for crewed spaceflight in 1965. By Apollo, it was mission equipment rather than a lucky personal accessory. The choice had a quiet logic. A watch could travel with an astronaut, work inside or outside, and measure an interval without asking the spacecraft for power. You can call that redundancy.

In the middle of a crisis, it feels more like having one extra chance. When Apollo 11 landed on the Moon, Neil Armstrong faced a strange choice: take his Speedmaster outside, or leave it in the lunar module. He left it inside. The module's timer had caused trouble, and a watch could serve as a backup while Buzz Aldrin took his own onto the surface. That is how the astronauts later remembered the decision. The man to step onto the Moon left his watch indoors. The famous photograph was less important than having a way to keep time inside the lander. The Speedmaster earned its nickname on the Moon. The next chapter would show a different side of it. A mission that never reached the lunar surface would need every backup it had. Apollo 13 had a landing site and a crew of three. Jim Lovell was the commander. Fred Haise was the lunar module pilot. Jack Swigert joined at the last minute, replacing Ken Mattingly after a measles scare.

Swigert wore a Speedmaster. His flight watch is now in the Smithsonian collection. It was a small part of the equipment on board and, at first, hardly the most exciting thing to watch. For nearly two days, the flight was routine enough that a controller in Houston joked they were bored. Then the crew finished a television broadcast. Nine minutes later, an oxygen tank exploded. A bang shook the spacecraft. Alarms followed. Within hours, the Moon landing was gone. The new mission was simpler to say and much harder to do: bring all three men home. The command module lost its normal supply of electricity, light and water. Imagine your house suddenly losing all three, then remember that this house is moving through space. crew moved into the lunar module, a machine built to carry two people down to the Moon and back. Now it had to keep three people alive long enough to return to Earth. At Mission Control, teams wrote and tested new procedures while the astronauts dealt with a cold cabin, dwindling water and an air system that needed an improvised fix.

The watch cannot clean the air or tell Houston where the spacecraft is. But the rescue is made of hundreds of small jobs. Some require a room full of engineers. Others require someone to count seconds accurately while the engines run. First, the crew had to get back onto a path around the Moon and toward Earth. They fired the lunar module's engine. Later, after swinging past the far side, they fired it again to shorten the journey and change where they would land. Each maneuver bought them a better chance. But they still had to arrive at Earth at the right angle. Too shallow and the craft could skip away. Too steep and reentry would become dangerous. Their remaining power and water were too precious to use the lunar module's computer for every task. For one final short correction, NASA had another plan. The men would aim by looking at Earth and the Sun through the windows, fire the engine by hand, and stop it at the right second. Earth was still about 175,000 miles away. The engine starts. Lovell keeps the spacecraft lined up. Swigert has the seconds. A few moments later, the engine stops. The firing lasts 14.8 seconds, and NASA says it makes the correction they needed.

It is the kind of scene that sounds invented. A spacecraft is trying to return from the Moon, and one of the useful tools is a watch that needs no battery from the ship. But that is why NASA had tested it and sent it in the first place.

Houston had worked out the maneuver. The crew still had to do it, in a damaged, freezing spacecraft, without the computer they would normally have used for the timing. This is where a backup stops sounding boring. The story is sometimes condensed into one line: a watch saved Apollo 13. It is catchy. It also misses the people who made the rescue possible. The watch could measure an interval. It could not calculate the course, hold the spacecraft steady or make the engine fire.

That was the work of the crew and the teams in Houston. A good backup does not replace them. It gives them one more dependable tool when the normal plan has failed. And the most surprising part is that the watch had been there all along. It did not arrive as a rescue device. It was standard equipment, chosen years before anyone knew what would happen to this crew. Apollo 13 never landed on the Moon. But Lovell, Haise and Swigert came home. NASA later called it a successful failure: the landing failed; the rescue succeeded. The Speedmaster already had its Moon story. Armstrong had left his inside the lander to back up a troublesome timer; Aldrin took his onto the surface. Apollo 13 gave the watch a different kind of moment. Nothing glamorous. Just seconds that mattered when the spacecraft's systems could not do every job. That is why NASA trusted a wristwatch in space. It had been tested. The crew knew how to use it. And it could keep counting when they needed to save the spacecraft's power for the journey home. The most famous watch in space did not have to be a hero. It only had to be ready.