5. Toxic Effects of Martian Dust on Humans

2005: IVA-2
2010: 2C
Priority: Medium

2010 Version

2C. Investigation. Determine the possible toxic effects of martian dust on humans.

A discussion about the importance of the potential toxic effects of martian surface materials is detailed in the NRC report, “Safe on Mars (2002),” by the Committee on Precursor Measurements Necessary to Support Human Operations on the Surface of Mars. They considered the presence and distribution of CrVI, commonly called “hexavalent cromium,” especially important to understand because it is a strong human carcinogen. None of the past missions to Mars have carried instrumentation capable of measuring this species. Also discussed in the report are other potential cancer causing compounds, many of which are still of concern due to lack of sufficient data. Potential chronic effects like lung injury in the form of silicosis must also be studied in greater detail, preferably with a returned sample. Collection of data related to the measurements listed above was considered of highest priority from a risk perspective because the risk of insufficient data goes directly to the probability of loss of crew (pLOC). In terms of impact on design it was of comparatively less importance given the fact that EVA systems, as well as dust mitigation protocols and design features, would already be significant, driven by other environmental challenges and forward and back contamination protocols. Overall this investigation was seen to be of “medium” priority.

Measurements:
a. Assay for chemicals with known toxic effect on humans. Of particular importance are oxidizing species (e.g., CrVI) associated with dust-sized particles. May require a sample returned to Earth as previous assays haven’t been conclusive enough to retire risk.
b. Fully characterize soluble ion distributions, reactions that occur upon humidification and released volatiles from a surface sample and sample of regolith from a depth as large as might be affected by human surface operations. Previous robotic assays (Phoenix) haven’t been conclusive enough to significantly mitigate this risk.
c. Analyze the shapes of martian dust grains with a grain size distribution (1 to 500 microns) sufficient to assess their possible impact on human soft tissue (especially eyes and lungs).

Source:
MEPAG Goal IV Science Analysis Group (2010). “IV. Goal: Prepare for Human Exploration.”
Proposed replacement text for MEPAG (2008), Mars Scientific Goals, Objectives, Investigations, and Priorities. Submitted 2 August 2010.