In the months leading up to the 50th anniversary of the Apollo 11 mission, we will be sharing the stories of the people who made the moon landing possible as part of our Airlock space newsletter. First up is David Carrier, the mission’s lunar soil expert.

When William David Carrier went off to college at MIT, his dad advised him to do anything but go into aerospace. His father was a pilot and knew just how cyclical the industry was. But, as most college students do, Carrier ignored his father’s advice. “I ended up drawn like a moth to a flame to go work on the Apollo program,” he says.

During the Apollo missions, he served NASA as a lunar soil mechanics specialist and a principal investigator—an expert in moon dirt, in other words. Before the Apollo 11 moon landing, lots of crazy rumors were flying around about what lunar soil would actually be like. Would astronauts sink into the surface when they touched down? What if it wasn’t solid? Carrier decided he was going to brief the astronauts himself and settle any nerves.

Carrier helping with a drilling simulation at Cape Canaveral with Apollo 13 Astronaut Fred Haise. Courtesy of David Carrier

Down the hall from where he was working in Houston was the team of geologists tasked with giving them on-site training in El Paso. “The astronauts got the equivalent of a master’s degree in geology, basically, before they went to the moon,” says Carrier. “I made friends with the geologists and said, ‘Don’t you want me to help with the training?’ And they said, ‘Sure, come on—help us.’” He figured this could be his chance to grab the astronauts and impart his lunar soil wisdom.

But life got in the way. His wife was due to give birth before the training date, but as Carrier put it, “Our child wouldn’t be born.” With reluctance, he had to cancel on tagging along with the Apollo crew.