The first female American in space, Sally Ride, has died at age 61, being survived by her lesbian partner.

Sally Ride died yesterday after a seventeen-month battle with pancreatic cancer and it is only following her death that the 27-year relationship has been made public.

Ms Ride entered space on the Challenger shuttle in June 1983 becoming the first American woman, and youngest-ever American, to do so. Two Soviet female astronauts had already flown missions.

She said afterwards she was “sure it was the most fun I’ll ever have in my life.”

A statement on her website said she “lived her life to the fullest, with boundless energy, curiosity, intelligence, passion, joy, and love. Her integrity was absolute; her spirit was immeasurable; her approach to life was fearless.”

In 1982, she married astronaut Steve Hawley. Their marriage ended in divorce five years later.

For the first time, it has been revealed she had been in a relationship with Tam O’Shaughnessy, whom she had known since their childhood in California.

The pair wrote a series of children’s books together designed to promote interest in science among younger generations.

Ms O’Shaughnessy is the Chief Operating Officer and Executive Vice President for Content of Sally Ride Science, a company founded to develop science teaching materials for primary and secondary school children in the US.

US President Barack Obama was “deeply saddened” to hear of Ride’s death.

He said: “As the first American woman to travel into space, Sally was a national hero and a powerful role model.”

Ms Ride died on Monday in La Jolla, California.