John Glenn was the first person to snap a photograph of Earth from outer space. Neil Armstrong took the first picture from the moon's surface.
The original prints of those are among 445 rare photos taken by American astronauts that are being sold by Skinner Auctioneers and Appraisers starting this week.
The Massachusetts auction house says The Beauty of Space is the first US auction to focus solely on vintage photographs produced by Nasa astronauts during the heyday of space exploration, from 1961 to 1972.
The auction goes live on Thursday (12 October) and runs until 2 November.
The photographs are valuable not only for their scientific and historical significance, but also for their artistry, says Michelle Lamunière, a specialist in fine photography at Skinner.
"While the astronauts' primary goal was to record their activities, they were inspired by what they witnessed, creating images that transcend documentation," she said.
The images up for auction are not reprints but original, gelatin silver or chromogenic prints produced by Nasa following the Mercury, Gemini and Apollo missions.
Many bear original Nasa marks, captions and identifying numbers. Individually, the images are worth anywhere from $300 (£228) to $9,000 (£6,850), according to the auction house.
The photos were acquired by an unnamed private collector from former Nasa scientists and employees. They include astronaut portraits, candid shots during training exercises and dramatic images of spacewalks and views of the Earth and moon from space.
Among the standout photos is a 1962 image by John Glenn of the sun illuminating the Earth. It's the first photo of the planet taken by a human from space.
There's also Buzz Aldrin's 1969 picture of the first footprint on lunar soil (his own) as well as his colleague Neil Armstrong's famous "visor" photo from that same Apollo 11 mission.
Armstrong's photo captures Aldrin on the moon's surface, his gold-plated sun visor reflecting Armstrong and their lunar module.
And as President Donald Trump's administration promises to return astronauts to the moon, the collection offers a timely memento: a portrait of astronaut Eugene Cernan taking humankind's last stroll on the lunar surface in 1972.