Between May 1966 through January 1968, NASA launched seven Surveyor spacecraft to demonstrate the feasibility of soft landings on the Moon in preparation for Project Apollo.
Built by Hughes Aircraft Corporation, Surveyor probes were 10 feet in height, over 11 feet in diameter, and weighed approximately 625 pounds. Three landing legs extended about 14 feet from the spacecraft. Solar panels provided about 85 watts of power that was stored in rechargeable batteries. The probes were never meant to return to Earth. Five of the seven Surveyor probes successfully landed on the Moon (Surveyors 1, 3, 5, 6, and 7) in areas that were being considered for possible Apollo landing sites.
Surveyor probes were launched aboard Atlas-Centaur rockets from Cape Canaveral, Florida. They were sent on a direct trajectory to the Moon without being inserted into lunar orbit. Retro rockets slowed the spacecraft during its descent to the surface and engine cutoff occurred at approximately 14 feet above the surface. The spacecraft free fell the final few feet at about five feet per second. Crushable footpads and shock absorbers cushioned the fall.
NASA’s First Moon Landing
Surveyor 1 landed in the southwest region of Oceanus Procellarum (Ocean of Storms) on June 2, 1966, three months after the Soviet’s Luna 9 had soft-landed on the lunar surface. Surveyor 1 operated until June 13, transmitting over 11,000 pictures of the lunar surface. In addition to photography, Surveyor 1 confirmed that that the lunar surface could support the weight of a landing craft.
Testing the Lunar Soil
Surveyor 3 soft landed on the southeastern portion of Oceanus Procellarum on April 20, 1967. It was the first Surveyor probe to carry a surface sampler that dug seven-inch-deep trenches and manipulated the soil in view of its cameras. Surveyor 3 operated until May 4. Two-and-a-half years later, Apollo 12 landed within walking distance of Surveyor 3. The astronauts retrieved the probe’s camera and other components for study back on Earth.