Which NASA program sent uncrewed Surveyor landers to the Moon before Apollo?

NASA’s Surveyor program sent uncrewed landers to the Moon before the Apollo astronauts arrived.

Operating from 1966 through 1968, the program sent seven robotic spacecraft to the lunar surface. Its central purpose was to demonstrate that a spacecraft could perform a controlled soft landing and to study whether the lunar ground was safe for crewed missions.

Five Surveyor spacecraft successfully landed. Their cameras photographed the surface, while instruments examined soil composition and strength. Surveyor 1 became the first American spacecraft to make a soft landing on another celestial body. The missions helped engineers and Apollo planners understand lunar terrain, dust, and landing hazards.

The program is often confused with Ranger, which primarily sent impactor spacecraft to photograph the Moon during descent, or Lunar Orbiter, which mapped potential landing sites from orbit. Surveyor was specifically the lander program. Apollo 12 later visited Surveyor 3 and brought some of its parts back to Earth for study.