NASA left a camera on the moon for 31 months; when Apollo 12 brought it home, scientists found bacteria that appeared to be alive

On April 20, 1967, NASA landed an unmanned probe on the moon called Surveyor 3. Its camera was left alone for 31 months. Then, in November 1969, Apollo 12 astronauts walked over, removed the camera, and brought it home. Weeks later, scientists reported something odd: a common bacterium appeared to have been alive on the camera the entire time. According to a 2011 review by NASA-linked researchers, "A Microbe on the Moon? Surveyor III and Lessons Learned for Future Sample Return Missions," the real story is more complicated than the viral version.

A quiet visit to an old machine

Surveyor 3 was landed in the moon's Ocean of Storms. It was an automatic vehicle that would take pictures of the moon's surface and then simply shut down. However, on November 19, 1969, astronauts Pete Conrad and Alan Bean of the Apollo 12 mission landed their lunar module at a distance of about 163 meters away from it deliberately. They took apart the television camera of Surveyor 3 on their second moonwalk, November 20, 1969, putting it in a zipped sample bag. That is exactly 31 months from landing to retrieval, which is where the number in this story comes from. The crew splashed down on November 24, 1969. The camera was quarantined at NASA’s Lunar Receiving Laboratory and secured inside two Teflon bags. But it was not until about six weeks later, on Jan. 8, 1970, that technicians tested it for microbes.

One colony out of thirty-three samples

Researchers swabbed 11 different locations inside the camera to collect 33 samples. One was positive. One colony of Streptococcus mitis, a harmless bacterium that lives in the human mouth, was found on a small piece of polyurethane foam insulation material. The study notes no other viable microbes were found anywhere else in the camera or on any lunar surface samples Apollo brought back. If the bacteria had actually survived 31 months of near-vacuum and temperature swings from minus-150 to 120 degrees Celsius, it would have been an incredible survival story.

The clues that didn't add up

The 2011 study by John Rummel of East Carolina University, NASA's Judith Allton, and retired lunar lab scientist Don Morrison also noted another important point. According to the paper, Streptococcus mitis had also been isolated from Apollo 12 crew members during their post-mission health screening, testing done back on Earth, not during the moonwalk itself. Combined with the loose lab protocols captured on film, this suggests the bacterium most likely entered the camera during the weeks it sat in the lab before testing, whether from technicians handling it or from the astronauts during quarantine and health checks, not from anything that happened on the lunar surface.

The team managed to find the 16 mm film of the 1970 lab experiment session and examined it in detail. According to the authors, those who were operating the camera were wearing short-sleeve scrubs with their arms visible and loose masks that covered only some part of the face. No negative control had been done to check whether the room was contaminated. At one point, a lab technician moved inside the hood and looked directly at the uncovered inner surface of the camera. The co-author Don Morrison described the entire sequence quite bluntly: "The general scene does not lend a lot of confidence in the proposition that contamination did not occur."

What NASA and other scientists think now

Andrew Schuerger and colleagues' 2019 paper in the journal Astrobiology modeled how microbes behave on the lunar surface, taking into account its extreme heat, radiation, and vacuum. The authors state in this paper that they agree with the conclusions reached in 2011 that the recovery of Streptococcus mitis most likely represents contamination introduced during testing on Earth rather than survival on the moon. NASA's own Office of Planetary Protection still exists because of the questions this incident raised. Its mission is to prevent Earth microbes from contaminating other planets and to ensure returned space materials do not harm Earth. That mandate has only grown more detailed since: NASA updated its core planetary protection policy (NPR 8715.24) in 2021 and released a revised Planetary Protection Handbook in January 2025. The agency's Mars Sample Return program, which would bring back the first samples collected by the Perseverance rover, has faced repeated delays and budget uncertainty, with NASA still weighing between two landing architectures as it works toward a final decision, sample-handling and Earth-contamination safeguards built in from the start. Modern missions are assigned protection categories, and spacecraft destined for sensitive destinations undergo rigorous cleanroom assembly and sterilization before launch.

Why this old story still matters

The Surveyor 3 story shows how an eye-catching initial claim often gains traction quickly, but a careful rechecking of the patient, sometimes years or decades later, often changes the picture. A seemingly harmless detail about a very hardy bacterium on the moon became an important step in the way space agencies approach contamination both ways. So next time you see this story on your feed as evidence that bacteria have taken over space, remember the bigger picture. What they found was not that a germ lived through the moon, but that lab procedures needed to be much stricter, a lesson that taught NASA to be far more careful about what leaves this planet and what comes back.