She earned a masters degree in history and political science from Chico State University (now known as California State University, Chico). She met Eugene Shoemaker at her brother’s wedding, where Dr. Shoemaker, her brother’s former roommate, served as best man. They married a year later, in 1951.

Ms. Shoemaker worked briefly as a teacher after college, but when she got married she had given up her job. She accompanied her husband on field expeditions, cooked meals for him and his colleagues and raised the family’s three children.

Today professional astronomers use remote-controlled telescopes and digital recognition software. They don’t tend to spend entire nights in remote mountainous areas, wielding telescopes across the night sky and developing films in their own darkrooms like the shoemakers did. Yet scientists still rely on methods that Ms. Shoemaker has perfected.

“She and her colleagues set the stage to identify what we would call smaller bodies in our solar system, like comets and asteroids,” said Dr. Wiseman. “We still use the technique of looking for the relatively fast transverse movements of comets and asteroids in our own solar system compared to the slower or more fixed positions of stars.”

In addition to Mrs. Salazar, Mrs. Shoemaker has another daughter, Christine Abanto; one son, Patrick; three grandchildren; and five great-grandchildren.

In 1997 she and Dr. Shoemaker on a trip to Australia to investigate craters when they turned a corner on a remote road in the outback and collided with an oncoming car. Ms. Shoemaker broke her rotator cuff and fractured a rib and wrist. Dr. Shoemaker died instantly.

After the death of her husband, Ms. Shoemaker devoted herself to completing the research they had begun.

“Without genes, I would never have experienced the excitement of planetary science,” she wrote in her autobiographical essay. “Without me, he often said, his search for asteroids and comets and then the Australian crater work would never have been attempted. Together we could achieve more than each of us alone. “