Australian Journal of Earth Sciences

Geology dominated the science of the six successful Apollo lunar sampling expeditions. About 380 kg of rocks and soils were collected in 2400 samples, along with many thousands of documenting photos. Lunar dust shrouding Moonscapes, obscuring and coating rock samples, was a nuisance for geologist-advisers and plagued each astronaut with its inescapable presence, sticking to every surface. Lunar dust was judged by Apollo 17 geologist-astronaut Harrison Schmitt as ‘No. 1 environmental problem on the Moon.’ As fine as talcum powder but more abrasive than sandpaper, dust jeopardised vacuum sealing of sample containers to preserve rocks free from terrestrial contamination, just as later at Houston it jeopardised long-term archives of lunar samples. Yet the only one type of Apollo experiment to measure dust and its movements in situ was a matchbox-sized Dust Detector Experiment (DDE) weighing 270 g deployed on Apollo 11, 12, 14 and 15 Apollo Lunar Surface Experiment Packages (ALSEPs), which transmitted DDE data to Earth every 54 s between 21 July 1969 and 30 September 1977. This report by the Australian inventor and Principal Investigator of the minimalist DDE, designed to hitch-hike, outlines its discoveries of basic characteristics of movements and stickiness of lunar dust. Unexpected realities include effects of (1) an out-gassing aura metres in extent surrounding an astronaut and (2) contamination and heating effects of ‘collateral dust,’ lunar surface dust kicked up and splashed by astronauts on experiments and rock samples. Some interpretations of DDE data presented in Apollo-era literature are challenged and alternative interpretations are presented, with two Apollo-era dust discoveries not referenced for 40 years. Little-known potential contamination of Apollo experiments, Moon rock samples and photographic validity is discussed, together with ongoing discoveries of the basics of dust such as dynamic behaviour and long-term accretion.

Apollo measurements of lunar dust amidst geology priorities