Surveyor 3, was the third spacecraft in NASA’s uncrewed Surveyor program that made a soft landing on the Moon in 1967 to explore the lunar surface. Key points about Surveyor 3 include:
- Launched on April 17, 1967, Surveyor 3 successfully soft-landed on April 20, 1967 in the Oceanus Procellarum region of the Moon. It transmitted over 6,000 TV images back to Earth.
- Surveyor 3 was the first spacecraft to carry a surface soil sampling scoop that could reach up to 5 feet into the lunar soil to analyze its composition. Previous Surveyors carried TV cameras but no sampling capabilities.
- During its descent, highly reflective lunar rocks confused Surveyor 3’s radar and caused its main engine to fail to cut off at the right altitude. As a result, Surveyor 3 bounced twice on the lunar surface before settling down.
- In November 1969, Apollo 12 astronauts Pete Conrad and Alan Bean visited Surveyor 3, inspected it, photographed it extensively, and retrieved several components to return to Earth for analysis. This makes Surveyor 3 the only probe visited by humans on another world.
The retrieved Surveyor 3 components were transported to the Lunar Receiving Laboratory (LRL) at NASA’s Manned Spacecraft Center in Houston for analysis. The LRL was specially built for the quarantine and analysis of lunar material to prevent contamination of Earth. Key points about the LRL and analysis of Surveyor 3 components include:
- The LRL was constructed and operational by 1967 for initial analysis of lunar samples returned by Apollo missions. It had extensive quarantine protocols and specialized laboratories for analyzing lunar material.
- After retrieval from the Moon, the Surveyor 3 components and Apollo lunar samples were placed in quarantine at the LRL for preliminary examination before release. Quarantine periods for Apollo astronauts started at 21 days.
- In January 1970, analysis began on Surveyor 3 components like the TV camera. A bacterium, Streptococcus mitis, was isolated from a small piece of foam from inside the camera after the quarantine period.
- There was extensive consideration of potential contamination sources for S. mitis, including from the astronauts, lunar module, and retrieval and handling on Earth. Multiple lines of evidence suggest S. mitis was likely present in the camera prior to launch.
- S. mitis is a common bacterium from the human mouth and respiratory tract. Analysis suggests the bacteria survived launch conditions and lunar exposure through lyophilization (freeze-drying) and entered a dormant state. The lunar vacuum may have aided its survival.
- After studies were completed, some Surveyor 3 parts remained in storage at NASA while others were given out as commemorative displays and awards over the years. Their current locations are mostly unknown to the public.
Surveyor 3 provided critical data on the composition of the lunar surface and achieved the unique distinction of being the only space probe visited by humans on another celestial body. Analysis of its returned components offered early insights into the ability of some terrestrial microbes to survive the harsh lunar conditions.
