Surveyor 3

Surveyor 3
Name	Surveyor 3
Mission type	Lunar lander
Operator	NASA / Jet Propulsion Laboratory
COSPAR ID	1967-035A
SATCAT	02756
Mission duration	14 days (operational)
Spacecraft	Surveyor C
Manufacturer	Hughes Aircraft Company
Launch mass	1,036 kg (2,284 lb)
Landing mass	296 kg (652 lb)
Launch date	April 17, 1967, 07:05:00 UTC
Launch rocket	Atlas LV-3C Centaur-D
Launch site	Cape Canaveral LC-36B
Landing date	April 20, 1967, 00:04:53 UTC
Landing site	Oceanus Procellarum, 3.01° S, 23.42° W
Programme	Surveyor program
Previous mission	Surveyor 2
Next mission	Surveyor 4

Surveyor 3 was the third lander in the NASA Surveyor program to achieve a soft landing on the Moon. Launched on April 17, 1967, it touched down in the Oceanus Procellarum region, becoming the first spacecraft to land in a lunar mare. The mission is most famous for being visited over two years later by the crew of Apollo 12, who returned parts of the lander to Earth for analysis.

Mission overview

The primary objective of the Surveyor program was to demonstrate the feasibility of soft landings on the Moon in support of the upcoming Apollo program. Following the failure of Surveyor 2 and the success of Surveyor 1, NASA tasked Surveyor 3 with landing in a geologically different area, specifically a lunar mare, to gather engineering and scientific data. The mission was managed by the Jet Propulsion Laboratory and built by the Hughes Aircraft Company. Its successful landing and subsequent operations provided critical confidence for NASA planners ahead of crewed missions.

Spacecraft design

Based on the design of Surveyor 1, the spacecraft consisted of a tripod-like structure made of thin-walled aluminum tubing. It was equipped with a vernier engine and three retrorockets for the landing sequence. Key scientific instruments included a surface soil mechanics surface sampler, a television camera, and numerous engineering sensors. The television camera was mounted on a deployable mast and could be panned and tilted to provide a panoramic view of the landing site, a feature that proved vital for mission operations and the later Apollo 12 visit.

Landing and surface operations

The landing on April 20, 1967, was dramatic, as the spacecraft bounced twice on the lunar surface before coming to rest inside a small crater. This bouncing was caused by the vernier engines not shutting off immediately upon sensing touchdown. Despite this, the lander settled at a tilt of about 14 degrees. Over the following 14 Earth days, it transmitted 6,315 television images back to Earth. The surface sampler arm was used to dig trenches and manipulate soil, providing the first in-situ data on the mechanical properties of lunar regolith, crucial for designing Apollo program spacesuits and lander footpads.

Apollo 12 visit

On November 20, 1969, astronauts Pete Conrad and Alan Bean of the Apollo 12 mission landed their Lunar Module Intrepid approximately 180 meters from the Surveyor 3 site. During their second moonwalk, they walked to the lander, photographed it extensively, and removed several components, including the television camera, the surface sampler scoop, and pieces of tubing. These items were returned to Earth and analyzed by scientists at the Jet Propulsion Laboratory and other institutions, offering unique insights into the long-term effects of the lunar environment on human-made materials.

Scientific results

The mission confirmed that the lunar mare terrain was suitable for landing Apollo program spacecraft. Data from the soil mechanics experiments showed the surface could support the weight of a crewed lander. The trenching operations revealed a cohesive, soil-like material, likened to wet sand, providing vital engineering data. Images and sampler data helped calibrate interpretations of Lunar Orbiter photographs. The analysis of parts retrieved by Apollo 12 later revealed that the bacterium Streptococcus mitis had apparently survived launch, the space environment, and over two years on the Moon, a controversial finding that continues to be debated in astrobiology.

Legacy

Surveyor 3 stands as a landmark mission in lunar exploration, directly bridging robotic and human exploration. The engineering lessons from its landing sequence informed final designs for the Apollo Lunar Module. Its successful operations in Oceanus Procellarum validated the chosen landing site for Apollo 12. The Apollo 12 sampling of the lander remains a unique event in space history, a robotic artifact visited by humans. The spacecraft's components are now preserved for study, and its story is featured in museums like the National Air and Space Museum, symbolizing the iterative, preparatory nature of the Surveyor program for the triumph of Apollo.

Category:Surveyor program Category:Spacecraft launched in 1967 Category:Apollo program