Smithsonian.com

Flight director Gene Kranz looks at astronaut Fred W. Haise Jr., lunar module pilot, on the screen at Mission Control. (Courtesy NASA)

It was 40 years ago today, April 13, 1970, just two days after a three-man crew took off on Apollo 13′s mission to the moon, when Astronaut Jim Lovell told the flight directors in Houston, Texas, there was a problem.

An oxygen tank had ruptured, causing the spacecraft to lose its electrical power as well as the use of both of its oxygen tanks.

For the next four days, the country watched as the astronauts, who had intended to be the third American crew on the moon, now tried to repair the spacecraft so they could return safely back to earth. Despite limited power, the loss of most of the heat in the cabin, and  several quick makeshift repairs on the spacecraft’s carbon-dioxide remover, all three astronauts made it back safely on April 17, with the help of flight controllers on the ground in Houston.

Forty years later, though several books have been written about the incident, along with the 1995 film Apollo 13 , there are few people who have the chance to hear the story from the men involved in the mission itself.

To celebrate the 40th anniversary of Apollo 13, the National Air and Space Museum will give visitors a chance to do just that on Thursday as it hosts a panel lecture with several of the men involved in the spacecraft’s successful landing, including Lovell, Apollo 16 command module pilot Ken Mattingly, lunar module pilot Fred Haise, and flight director Gene Kranz (whose homemade white vest became a “can-do” symbol for his team while they worked to bring the Apollo 13 astronauts safely home).

The lecture, which begins at 8 p.m., is free but tickets are required. If you can’t make the event, watch a live webcast from the museum, or a video of museum curator Margaret Weitekamp as she talks about Gene Kranz’s career and how his famous white vest came to the museum’s collection.