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Lunar dust exposures occurred during the Apollo missions while the crew was in the lunar module on the moon's surface and especially when micro-gravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes, and in some cases, respiratory symptoms were elicited. NASA's current vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust in the habitat need to be assessed. NASA is performing this assessment with a series of in vitro and in vivo tests with authentic lunar dust. Our approach is to “calibrate” the intrinsic toxicity of lunar dust by comparison to a relatively low toxicity dust (TiO2) and a highly toxic dust (quartz) using intrapharyngeal instillation of the dusts to mice. A battery of indices of toxicity is assessed at various time points after the instillations.

Spacecraft modules that are last purged with clean air several months before they are entered by humans on orbit require careful management. The crew must not be exposed to harmful concentrations of air pollutants when they first enter. The magnitude of the pollution the crew will encounter depends on the volume of the module, the length of time since the last clean-air purge or scrub, the inherent offgassing rate of the materials in the module, the interior temperature of the module while offgassing occurs, and the system leak rate. The time of the last module purge or scrub can be several months before crew entry, so it is essential that the offgassing rate within the module be measured over a suitable interval of time to estimate pollution levels with confidence. Air samples were taken from the STS-74 Russian Docking Module, the STS-79 Spacehab, and the ISS Node 1 prior to launch to predict pollution levels at crew first entry.