Artemis 1, officially Artemis I and formerly Exploration Mission-1 (EM-1), was an uncrewed Moon-orbiting mission. As the first major spaceflight of NASA's Artemis program, Artemis 1 marked the agency's return to lunar exploration after the conclusion of the Apollo program five decades earlier. It was the first integrated flight test of the Orion spacecraft and Space Launch System (SLS) rocket, and its main objective was to test the Orion spacecraft, especially its heat shield, in preparation for subsequent Artemis missions. These missions seek to reestablish a human presence on the Moon and demonstrate technologies and business approaches needed for future scientific studies, including exploration of Mars.

In astronomy and spaceflight, a lunar orbit is an orbit of an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon a spacecraft is said to be at apolune, apocynthion, or aposelene. When closest to the Moon it is said to be at perilune, pericynthion, or periselene. These derive from names or epithets of the moon goddess.