Bear Ride, Dr. Sally Ride's sister, has described Sally Ride's partner Tam O'Shaughnessy as a member of the family.

Sally Ride, the first American woman in space, passed away Monday at the age of 61 after losing a prolonged 17-month battle with pancreatic cancer. She also held the distinction of being the youngest American in space.

Among those listed as survivors in Ride's obituary was O'Shaughnessy, who became romantically involved with Ride in 1985, just two years after she made history as the first American female in space aboard the NASA space shuttle Challenger.

Ride, often described as a private person, had not previously publicly discussed the relationship.

“We consider Tam a member of the family,” Bear Ride, Ride's sister, told

“People did not know she had pancreatic cancer, that's going to be a huge shock,” Bear Ride said.

“I hope [Sally Ride's coming out] makes it easier for kids growing up gay that they know that another one of their heroes was like them,” she added.

O'Shaughnessy is the executive vice president of Sally Ride Science, which is dedicated to supporting young students' interest in science, math and technology.