Mission Summary
Lunar Orbiter 1 was the first American spacecraft to successfully orbit the Moon and the first mission in NASA’s Lunar Orbiter program. Launched on August 10, 1966, the mission’s primary objective was to photograph potential landing sites for the upcoming Apollo and Surveyor missions while also studying the Moon’s gravity field, radiation environment, and micrometeoroid population. Entering lunar orbit four days after launch, the spacecraft marked a major milestone in preparing for the first human landings on the Moon.
Over the next month, Lunar Orbiter 1 photographed more than 5 million square kilometers (1.9 million square miles) of the lunar surface, returning 229 images, including 42 high-resolution and 187 medium-resolution photographs. The mission successfully identified and evaluated potential Apollo landing sites and collected valuable scientific data on the Moon’s gravitational field and radiation environment. On August 23, 1966, it also captured one of the first photographs of Earth as seen from lunar orbit, a landmark image in the history of space exploration.
Lunar Orbiter 1 demonstrated that detailed reconnaissance of the Moon from orbit was both practical and essential for crewed exploration. The mission laid the foundation for the four Lunar Orbiter missions that followed, providing the detailed maps and imagery that helped make the Apollo lunar landings possible. After completing its objectives, NASA intentionally crashed the spacecraft into the Moon on October 29, 1966, to prevent interference with future missions.
Sources and notes can be found on the Sources page.
