Effect of Apollo 11 lunar samples on terrestrial microorganisms.

Abstract

No living organisms were found in the Apollo 11 lunar material by the biological quarantine team at the Manned Spacecraft Center, Houston1,2. The same result was obtained in our independent search for living organisms in 50 g of Apollo 11 bulk fines, although iron-containing artefacts superficially resembling microbial clones were seen3,4. Several plausible explanations can be offered for the failure to detect living organisms in this lunar material. First, no living organisms were present in the sample when tested. Second, living organisms were present but the media and environments in which they were placed were not suitable for growth. A third possibility is that living organisms were present in suitable media and environments but that the lunar material inhibited growth. Taylor et al.5 reported that aqueous extracts of lunar material markedly inhibited the growth and survival of Pseudomonas aeruginosa. We now report the results of experiments designed to test Apollo 11 lunar samples for inhibition of the growth of terrestrial microorganisms in conditions resembling as closely as possible those used in our earlier search for living organisms in Apollo 11 lunar material.