Did Apollo 13 really say “Houston, we have a problem”?

What the crew actually said

Apollo 13 was the third planned Moon landing, aimed at the Fra Mauro highlands. It lifted off on April 11, 1970, with Jim Lovell, Jack Swigert and Fred Haise. Swigert had joined the crew only days before launch, after the original command module pilot, Ken Mattingly, was exposed to German measles. On the evening of April 13, Houston time, nearly 56 hours into the flight and more than 300,000 kilometers from Earth, Mission Control asked the crew to stir the oxygen tanks, a routine chore. Moments later the crew felt a jolt.

The Apollo Flight Journal transcript shows two voices overlapping: Swigert began “Okay, Houston,” Lovell echoed “Houston,” and Swigert finished the sentence.

Okay, Houston, we’ve had a problem here.

The capsule communicator, Jack Lousma, answered “This is Houston. Say again, please.” Lovell repeated it, with the technical detail:

Ah, Houston, we’ve had a problem. We’ve had a Main B Bus Undervolt.

An undervolt meant a sudden drop in power on one of the two main electrical circuits of the command module. Haise added that they had heard “a pretty large bang.” About fourteen minutes later Lovell looked out of a window and reported what Houston’s instruments could not show: “We are venting something out into the… into space.”

What had happened

Oxygen tank number 2, in the service module behind the crew, had failed. NASA’s review board, chaired by Edgar Cortright, traced it to damage done before launch: thermostatic switches in the tank heater were rated for the spacecraft’s 28 volts, not the 65 volts used on the ground, and during a tank-emptying procedure at the Cape they had welded shut, letting the heater overheat and burn the insulation off wires inside the tank. When Swigert switched on the tank fans, the bare wiring started a fire. The blast also damaged the other oxygen tank, which leaked away over the next hours. Without oxygen, the fuel cells that made the command module’s electricity and water began to die. The landing was off.

The lunar module as a lifeboat

The crew shut down the command module, Odyssey, to save its batteries for reentry, and moved into the lunar module, Aquarius, built to keep two men alive for a short stay on the Moon. It kept three alive for about three and a half days. They looped around the Moon and used Aquarius’s descent engine to set and speed their course home. The cabin fell to near freezing, and carbon dioxide built up until engineers in Houston worked out how to fit the command module’s square filter cartridges into the lunar module’s round sockets, using plastic bags, cardboard and tape. On April 17, 1970, Odyssey splashed down in the South Pacific.

Where “we have a problem” comes from

In 1995 Ron Howard’s film Apollo 13, based on Lovell’s book Lost Moon (1994, written with Jeffrey Kluger), gave the line to Tom Hanks as Lovell, in the present tense: “Houston, we have a problem.” The same film gave the flight director Gene Kranz, played by Ed Harris, the line “Failure is not an option.” The words came from the screenwriters, not from the mission; Kranz later used them as the title of his memoir in 2000. The film’s version is now the standard way to announce, usually with a smile, that something has gone wrong. Another famous Apollo line has a misquote of its own: Armstrong’s missing “a”.