Margaret “Hap” Brennecke: The woman who welded Apollo’s rockets

The first female welding engineer employed at NASA's Marshall Space Flight Center made critical contributions to the mighty Saturn V that put men on the Moon.
By | Published: July 11, 2019 | Last updated on May 18, 2023
Margaret W. “Hap” Brennecke in 1964.
By the time she arrived at NASA, Margaret Brennecke, who usually went by the nickname “Hap,” was an old hand at engineering. And when the the Saturn V rocket launched the astronauts of the Apollo program to the Moon, it was in part thanks to Brennecke’s work.

Born in 1911, Brennecke earned her degree in chemistry from the Ohio State University in 1934 and continued on with graduate research in metallurgy at the Carnegie Institute of Technology in Pittsburgh, Pennsylvania; the University of Pittsburgh; and the University of California in Los Angeles.

She went on to work as a metallurgist for the Aluminum Company of America (Alcoa) for 22 years, including during World War II. Her work included finding the best materials and welding techniques for aircraft, bridges, and even the landing craft made famous during the D-Day invasion at Normandy in 1944.

Building the mighty Saturn

Brennecke made the leap to NASA in 1961, at the beginning of the Apollo program. In a 2004 oral history interview conducted by NASA, she recalled her thoughts on the change in employment: “When NASA came into being, I was intrigued. I remember [President John Fitzgerald] Kennedy in May 1961 came up with a challenge to the Moon before the end of the decade. … I was thrilled with the prospect of being involved in this challenge, particularly with its ‘we will win’ leadership. I [had] been in Russia in 1958 and I wanted desperately for the U.S. to get ahead of the Russians in space. To me, here was our opportunity and I could be a part of it.”

She joined NASA’s Marshall Space Flight Center as a welding expert, working specifically on the mighty Saturn rockets that made up the backbone of the space age. The Saturn V rocket, used for the Apollo missions, is still the only vehicle to ever carry humans beyond low-Earth orbit.

For the enormous Saturn stages, NASA needed materials that was both lightweight and strong. Thanks to her extensive experience, little of what Brennecke did was literal welding with a blowtorch in hand. Instead, she was responsible for deciding which materials and techniques should be used for the rockets. Brennecke’s major contribution was to craft the cryogenic fuel tanks. These tanks not only held supercooled fuel, they would also be subject to intense heat during launch. The weld points between different sections needed to be strong and immune to leaks. Brennecke helped to ensure the final results was what NASA needed to succeed.

Brennecke and Ernest Bayless at work in the Manufacturing and Engineering Laboratory at Marshall Space Flight Center in 1964.

Pushing boundaries

Brennecke published several scientific papers during her time at NASA, and her supervisor recommended her for an award from the Society of Women Engineers for her “outstanding accomplishments vital to the success and timeliness of the Saturn Space Vehicle and other NASA programs.”
Still, Brennecke didn’t recall everyone being so supportive of her accomplishments. “I had to work twice as hard,” she said during her oral history interview, “particularly when either of my immediate supervisors would interfere with what I was trying to do. They would give me an assignment and the next thing you know, they were playing some kind of a trick. You learn there is such a thing as survival. You learn how to go around or up or down.”
She recalled a specific instance when a higher-up attempted to change her official job description from physical metallurgist to physicist. “This might sound stupid,” she said, “but he basically wanted to eliminate a position. By making me a physicist, [he tried to imply] I did not belong there and I sure as hell did not want to be a physicist.” She went over his head, “doing what you are never supposed to do,” as she put it, and told the top boss. Her title as metallurgist remained.
She credits her nickname to smoothing the way much of the time. “Hap,” she pointed out, “does not give you any clue to ‘he’ or ‘she.’” But her coworkers, searching for a middle ground between the courtesy of the times and the informality of the shop, tended to call her Ms. Hap. It turned into a joke, with her hardhat reading MISHAP. “It was not appreciated by the safety inspector. He did not think that was funny at all,” she said, laughing herself.

As the Apollo and Saturn programs wound down, Brennecke remained with NASA. She transferred to selecting materials and techniques for Spacelab and the Space Shuttle’s booster rockets, ushering in the next era of NASA’s human space exploration. Brennecke died in 2008.