Ironically, one of the most enduring accomplishments of man's last voyage to the moon is a snapshot - of our own planet.
Dubbed "The Blue Marble," the image arguably has changed the way humankind thinks of Earth. Thirty years later, it remains NASA's most-requested picture and may be the most-reproduced image in history, says NASA archivist Mike Gentry.
On Dec. 7, 1972, five hours after blasting off from the Kennedy Space Center in Florida, the crew of Apollo 17 was about 25,000 miles from home when they saw it: a resplendent Earth in a sea of icy blackness. An astronaut (no one is certain who) aimed a Hasselblad camera out the window and captured this indelible image.
The photograph differed from the 1968 Apollo 8 photo "Earthrise," humans' first view of Earth from space. "Earthrise" showed a lunar landscape in the foreground with a partially shadowed Earth rising beyond it. "The Blue Marble" showed a full Earth, thanks to a flight path that took Apollo 17 over the Southern Hemisphere at midday at the height of the southern summer.
Environmental groups quickly seized upon the image as one that conveyed Earth's beauty and vulnerability. Famine-relief organizations used it as a symbol, noting the prominent position of Africa in the photo. Others saw the borderless globe as a way to ponder the possibility of a world without political or national boundaries.
Today, virtually every picture showing a full Earth is derived from this photograph. Television, magazines, websites, posters, and T-shirts all feature this image, yet few people notice that it is the same one.
Since Apollo 17, "there have been unmanned satellites that have taken pictures of Earth," Mr. Gentry says. "[But none] have taken nearly that majestic a picture."