Apollo 11 astronaut Michael Collins has died aged 90, his family has said.
Collins was called the "forgotten astronaut" because he stayed aboard the command module as Neil Armstrong and Buzz Aldrin made the historic 1969 moon landing.
The statement from his family said: "We regret to share that our beloved father and grandfather passed away today, after a valiant battle with cancer.
"He spent his final days peacefully, with his family by his side. Mike always faced the challenges of life with grace and humility, and faced this, his final challenge, in the same way.
"We will miss him terribly. Yet we also know how lucky Mike felt to have lived the life he did. We will honour his wish for us to celebrate, not mourn, that life.
"Please join us in fondly and joyfully remembering his sharp wit, his quiet sense of purpose, and his wise perspective, gained both from looking back at Earth from the vantage of space and gazing across calm waters from the deck of his fishing boat.
"Our family asks for privacy during this difficult time. Details on services will be forthcoming."