The sheriff’s office of San Juan County, Wash., said in a statement that a two-seater plane went down into the waters near Jones Island in the San Juan Channel on Friday morning. San Juan County Sheriff Eric Peter said that the cause of the crash is being investigated and that it appeared the pilot was the only person on board at the time.

The Apollo 8 mission of 1968 — the first crewed mission to orbit the moon — carried three astronauts: Frank Borman, James Lovell Jr. and Bill Anders.

On Christmas Eve, Mr. Anders captured one of the most significant photographs ever taken: a blue planet, small and vulnerable, floating in the intimidating vastness of space.

“As I looked down at the Earth, which is about the size of your fist at arm’s length, I’m thinking, ‘This is not a very big place. Why can’t we get along?’” Mr. Anders said in a video played to celebrate the 50th anniversary of the Apollo 8 mission in 2018, The Washington Post reported.

“To me it was strange that we had worked and had come all the way to the moon to study the moon, and what we really discovered was the Earth.”

NASA Administrator Bill Nelson said Friday that Mr. Anders had “offered to humanity among the deepest of gifts an astronaut can give.”

“He traveled to the threshold of the Moon and helped all of us see something else: ourselves,” Nelson wrote on social media. “He embodied the lessons and the purpose of exploration. We will miss him.”

Mr. Anders was born in 1933 in Hong Kong, where his father, a naval officer, was stationed, according to the Heritage Flight Museum. (Mr. Anders founded the museum, now located in Burlington, Wash., with his wife.)

The family later moved to California, where he graduated high school. He went on to achieve an engineering degree at the U.S. Naval Academy and earned his pilot’s wings with the Air Force in 1956. Mr. Anders graduated from the Air Force Institute of Technology in 1962 with a degree in nuclear engineering, specializing in space radiation. He was tapped by NASA the following year.

At age 35, Mr. Anders was one of the first three people to leave Earth’s orbit through the Apollo 8 mission. The spacecraft circled the moon 10 times before it splashed down into the Pacific Ocean a little more than 147 hours, or about six days, after launch, according to NASA. The following year, Neil Armstrong and Buzz Aldrin would walk on the moon’s surface.

Borman, Lovell and Mr. Anders were named Time magazine’s Men of the Year for 1968.

In a live broadcast on Dec. 24, 1968, the crew read the first 10 verses of Genesis from space to an audience of half a billion people, according to the National Archives.

The same day, Mr. Anders took his famous photograph.

The National Archives writes of the picture: “The crew of Apollo 8 was armed with still and movie cameras to photograph the Moon; but the most enduring image of their mission is this photograph of their own home, planet Earth.” Decades later, the impact of the photograph is still regularly cited.

In a 2018 interview with the Guardian, Mr. Anders said the image changed him, too. “It really undercut my religious beliefs. The idea that things rotate around the pope and up there is a big supercomputer wondering whether Billy was a good boy yesterday? It doesn’t make any sense.”

After NASA, Mr. Anders served on government commissions and councils, and was the U.S. ambassador to Norway. He had stints in the private sector, including as the chief executive of General Dynamics, an aerospace and defense company, before he retired to Washington state and took up air racing.

He and his wife, Valerie (Hoard) Anders, were married in 1955 and have six children.