Apollo 8
Apollo 8, the second manned mission in the American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Apollo space program, was the first human spaceflight
Human spaceflight
Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....

 to leave Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 orbit; the first to be captured by and escape from the gravitational field of another celestial body; and the first crewed voyage to return to Earth from another celestial body—Earth's Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. The three-man crew of mission Commander Frank Borman
Frank Borman
Frank Frederick Borman, II is a retired NASA astronaut and engineer, best remembered as the Commander of Apollo 8, the first mission to fly around the Moon, making him, along with fellow crew mates Jim Lovell and Bill Anders, the first of only 24 humans to do so...

, Command Module Pilot James Lovell
Jim Lovell
James "Jim" Arthur Lovell, Jr., is a former NASA astronaut and a retired captain in the United States Navy, most famous as the commander of the Apollo 13 mission, which suffered a critical failure en route to the Moon but was brought back safely to Earth by the efforts of the crew and mission...

, and Lunar Module Pilot William Anders
William Anders
William Alison Anders is a former United States Air Force officer, NASA astronaut, businessman, and engineer. He is, along with Apollo 8 crewmates Frank Borman and Jim Lovell, one of the first three persons to have left Earth orbit and traveled to the Moon .-Biography:Anders was born to Arthur...

 became the first humans to travel beyond low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

, the first to see Earth as a whole planet, and then the first to directly see the far side of the Moon
Far side of the Moon
The far side of the Moon is the lunar hemisphere that is permanently turned away, and is not visible from the surface of the Earth. The far hemisphere was first photographed by the Soviet Luna 3 probe in 1959, and was first directly observed by human eyes when the Apollo 8 mission orbited the Moon...