NASA scientist Claudia Alexander, who was a project manager for the Galileo spacecraft mission to Jupiter and worked on the European Space Agency’s Rosetta comet chaser, has died at age 56.

Alexander died on July 11 after a 10-year battle with breast cancer, NASA said on its website this week. The post did not say where she passed away.

“Claudia brought a rare combination of skills to her work as a space explorer,” Charles Elachi, director of NASA’s Jet Propulsion Lab in Pasadena, California, said in a written statement.

“Of course with a doctorate in plasma physics, her technical credentials were solid,” Elachi said. “But she also had a special understanding of how scientific discovery affects us all, and how our greatest achievements are the result of teamwork, which came easily to her.”

Born in Canada, Alexander moved at a young age with her family to California’s Silicon Valley, where she grew up.

She began working at the Jet Propulsion Laboratory in 1986 when she joined the team behind the Galileo spacecraft, three years before it was launched on a mission to study Jupiter and the planet’s moons.

She later became the Galileo mission’s final project manager. In 2003, she oversaw the end of the spacecraft’s odyssey when it was purposely set on a collision course to disintegrate in the planet’s dense atmosphere.

“We learned mind-boggling things,” Alexander said at the time. “This mission was worth its weight in gold.”

In 2000, Alexander was chosen as the lead U.S. project scientist on the European Space Agency’s Rosetta mission to the comet 67P/Churyumov-Gerasimenko.

Rosetta is the first spacecraft to orbit a comet’s nucleus and last year a lander from the Rosetta mothership made the first soft-landing on a comet.

She told the Los Angeles Times in an interview last year that, as an African-American woman in a field largely filled with white males, she was able to effectively act as a bridge between NASA and the European Space Agency.

“I’m used to walking between two different cultures,” she told the newspaper. “For me, this is among the purposes of my life — to take us from states of ignorance to states of understanding with bold exploration that you can’t do every day.”