When the United States launched the space race in the 1940s, Yvonne Brill was the only woman working on rocket projects in the entire country. The Canadian chemist and engineer created technology that revolutionized satellite maneuvering in orbit. Her invention still operates in space today, although the inventor herself spent years in the shadow of her male colleagues.
A Lone Woman Among Engineers
Yvonne Brill graduated from the University of Manitoba with a bachelor’s degree in mathematics and chemistry while only in her early twenties. Her ambition led her to Los Angeles, where she joined Douglas Aircraft Company as a mathematician on the project to build the United States’ first artificial satellite. At the time, the aerospace and space industries were exclusively male domains, and the young Canadian had to prove her worth every day.
Alongside her professional work, Brill continued her studies at the University of Southern California, preparing for her master’s exams in chemistry. This dual track required extraordinary determination and time management. But the young scientist was not satisfied with simply being a mathematician performing calculations for other designers.
After earning her master’s degree, she moved to the East Coast, where she began a career as a chemical engineer. Her interests focused on the efficiency of jet engines and the chemical factors affecting their operation. These foundations of knowledge would soon result in a groundbreaking invention that changed the face of satellite technology.
An Extraordinary Invention
The story of the electrothermal engine powered by hydrazine began, paradoxically, as a side project. In her spare time, Brill studied the problem of satellite maneuvering once they were in orbit. Her official duties did not cover this area, but her scientific curiosity would not let her ignore the technical challenge.
The outcome of these private studies was the so-called resistojet: an engine that uses electric heating of hydrazine to generate thrust.
This technology dramatically improved the efficiency and reliability of satellite propulsion systems. Previously, keeping satellites in the correct orbits was one of the greatest challenges of space engineering.
Brill’s invention solved the problem of precise orbital corrections with minimal fuel consumption. Satellites equipped with her engines could remain operational longer and perform more complex maneuvers. This innovation opened new possibilities for satellite telecommunications, meteorology, and space research.
From the Apollo Program to Mars Probes
Yvonne Brill’s career included the most prestigious projects of the American space program. She worked on the design of the Nova rockets for the Apollo Program, which ultimately sent humans to the Moon. Her expertise in chemistry and engineering proved invaluable in solving propulsion challenges.
Brill was also in teams responsible for the first American weather satellite and the first satellite placed in the stratosphere. These pioneering missions demanded innovative technical solutions, which the Canadian engineer consistently provided. She also worked on the engine powering space shuttles, the backbone of American manned flights for decades.
Her last major project was the Mars Observer probe, designed to study the Red Planet. Although the mission failed for reasons unrelated to Brill’s work, her contributions to interplanetary probe technology remain lasting. In 2011, President Barack Obama honored her with the National Medal of Technology for her lifetime achievements, confirming her place among the most important figures in American astronautics.
Rory Thornfield
Rory's grandfather left behind a wartime diary filled with accounts of a minor Burma skirmish that history books never mentioned. Reading it, Rory realized: behind every famous battle are dozens of forgotten struggles, each with its own human drama.
His preferred topics: The overlooked corners of military history – secondary campaigns, shadow battalions, local conflicts that never made headlines. From medieval sieges to twentieth-century expeditions, he focuses on the soldiers, not the generals. The people who faced impossible choices and carried those experiences forever.
Rory strips away the romanticism without losing respect for those who served. He combines tactical analysis with personal stories, examining human endurance and moral complexity rather than celebrating warfare. His writing is balanced, thoughtful, and deeply researched.
Outside work, Rory visits forgotten battlefields (now quiet farmland), photographs war memorials nobody tends anymore, and interviews veterans' families.