Michael Collins, one of the three crew members on the historic Apollo 11 - has sadly passed away at the age of 90.
Per BBC News, his family confirmed the news, stating that the astronaut died on Wednesday following "a valiant battle with cancer. He spent his final days peacefully, with his family by his side".
Collins was a crucial part of the historic first manned mission to the Moon back in 1969, but his name is seldom mentioned alongside crewmates Neil Armstrong and Buzz Aldrin.
This is because, as Armstrong and Aldrin walked the Moon's surface, Collins had stayed in the command module in lunar orbit. In doing so, Collins was given the nickname of the "forgotten" astronaut.
A statement from his family reads: "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 honor 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."
A statement from NASA recognizes that Collins' time aboard the command module without Aldrin and Armstrong resulted in him earning the nickname of the "the loneliest man in history".
Describing Collins as a "true pioneer and lifelong advocate for exploration", NASA's statement added: "While his colleagues walked on the Moon for the first time, he helped our nation achieve a defining milestone. He also distinguished himself in the Gemini Program and as an Air Force pilot."
The space agency then shared a quote from Collins himself, which reads:
"Exploration is not a choice, really, it’s an imperative,’ he said. Intensely thoughtful about his experience in orbit, he added, ‘What would be worth recording is what kind of civilization we Earthlings created and whether or not we ventured out into other parts of the galaxy."
BBC News adds that approximately 400,000 people worked on the Apollo 11 program, which amounted a total cost at the time of $25 billion.
Per the Independent, Collins also served in the US Air Force - and clocked up over 3,000 hours flight time throughout the 50s and early 60s.
He also shared three children with his wife, Patricia Finnegan, whom he married in 1957, and would remain married to until her death in 2014.
At the age of 91, Buzz Aldrin is now the only serving crewmate of Apollo 11, as Armstong passed away in 2012 at the age of 82.
Our thoughts are with Michael's family and loved ones at this time.