Pioneering rocket scientist Yvonne Brill often referred to herself as an "only" — as in the sole woman in the room at a time when female scientists and engineers were exceedingly few.
Brill began her career in 1945 and eventually developed a revolutionary propulsion system that remains the industry standard for keeping unmanned spacecraft in constant, stationary orbit. Later in her career, she became the director of the space shuttle's solid rocket motor program for NASA.
In the last quarter-century of her life, she strove to help others pursue careers in science and math and especially pushed for women to achieve scientific recognition.
Brill continued to write award-nomination letters until days before she died March 27 at a Princeton, N.J., hospital, her family said. She was 88.
The cause was complications of breast cancer, said her daughter, Naomi.
In 2011, at a White House ceremony, President Obama awarded Brill the National Medal of Technology and Innovation, the nation's highest honor for engineers and inventors.
"She was a mentor, a champion and a role model for so many of us," said Jill Tietjen, a former president of the Society of Women Engineers. "She was determined, absolutely determined to help young engineers and scientists get to the next step and get the awards and recognition they deserved."
An expert in the chemistry of space propulsion, Brill learned to push hard for projects and ideas she believed in.
"I never was afraid to risk my job to further ideas that I thought should be adopted, that were good technical ideas, that maybe somebody considered were a little bit far out," she said in a 2005 interview for a Society of Women Engineers publication. "I just kept pushing. I didn't care whose shins I kicked.... And the ideas got adopted."
In 1987, she was elected to the National Academy of Engineering, becoming one of its few female members.
She often talked about how she successfully juggled a demanding career and family life but said it wasn't easy. She was married for nearly 60 years to William Brill, a research chemist; the couple raised three children, all of whom, at least initially, pursued engineering and scientific careers.
Brill's husband died in 2010. Her survivors include her children, Naomi, a retired mechanical engineer; Matt, a geologist who works in environmental remediation, and Joe, a commercial real estate developer with degrees in electrical engineering and business; and four grandchildren.
When her children were young, Brill worked part time for several years, returning to the workplace full time in 1962.
She liked to point out to students and younger colleagues that she achieved her greatest career successes after age 40.
Yvonne Madelaine Claeys was born Dec. 30, 1924, near Winnipeg, in the Canadian province of Manitoba. Her parents had emigrated from Belgium and her father had a carpentry construction business
The youngest of three children, she did well in school but didn't realize her potential until she started getting top grades in high school. She went on to the University of Manitoba, hoping to study engineering, but was told women could not enroll in that department. An engineering summer camp was required, she later recalled, and "they said they just couldn't do special arrangements for women."
After receiving a bachelor's degree in mathematics from the university in 1945, she accepted a job offer from the Douglas Aircraft Co. in Southern California. She moved to Los Angeles alone, diving into her career and developing an interest in the chemistry of propellants while working as an engineer.
She specialized in rocket propulsion for what became the Rand Corp. and took graduate classes in the evening at USC, earning a master's degree in chemistry in 1951.
While attending a lecture by noted chemist Linus Pauling, she met her future husband, who was doing postdoctoral research in chemistry at UCLA. They were married in 1951 and immediately faced a challenge. His career opportunities were on the East Coast, while most of hers were in the west.
They decided to move east, settling eventually near Princeton. Yvonne Brill worked for several companies before starting at RCA Astro Electronics in 1966.
Soon after returning to full-time work, she invented the hydrazine resistojet, also known as the electrothermal hydrazine thruster, which uses a single propellant to keep communications satellites aloft and on a steady orbit, significantly decreasing the amount of propellant needed.
Since 1983, it has been used on satellites for RCA, General Electric, Lockheed Martin and other companies.
Yvonne Brill often said the decision to move east with her husband was based on her belief that "good jobs are easier to find than good husbands."
The saying, which became part of Brill family lore, was "meant to highlight the fact that engineering can be portable," her daughter said, "that you can have a job and a family."