Planning for the Scientific Exploration of Mars by Humans By the mepag human Exploration of Mars Science Analysis Group (hem-sag)
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Atmosphere/Climate: Human Exploration Goals and ObjectivesWhat are the key scientific goals and objectives of human exploration of Mars atmosphere/climate and what are sample Human Science Reference Missions (HSRM) in atmosphere/climate?SummaryAtmosphere and Climate goals and objectives are less site-specific than geology or biology, with the notable exception of climate studies associated with polar ice cap drilling. In Appendix B, we emphasize updated atmospheric and climate objectives and the degree to which they may be advanced by general rather than site-specific human exploration activities on Mars. Key scientific goals and objectives of Human Exploration for Mars (HEM) for the atmosphere/climate are summarized in Table 6.
HEM Atmospheric Objectives focus on processes within the Planetary Boundary Layer (PBL, surface to ~10 km), where surface-atmosphere interactions impart fundamental influences on the dynamical, chemical, and aerosol characters of the global Mars atmosphere. Orbital remote sensing for this region remains difficult and lander/rover atmospheric payloads limited such that sufficiently detailed measurements of the PBL are unlikely to be returned from Mars science missions prior to 2030. Field study of the PBL on Earth remains the preferred method of advancing understanding, with intensive campaigns using combinations of automatic weather stations, mobile surface-based atmospheric sounders, and balloon borne sonde platforms. HEM atmospheric observations could provide optimum in situ and remote access to the PBL important not only to the understanding of global Mars Atmosphere and Climate, but also to the support of HEM operations and as environmental characterization essential to the interpretation of many biology and geology objectives. HEM Polar Cap objectives are included as of high scientific value, but are understood to be challenging due to polar night considerations. A third class of activity is associated with the early evolution of climate and would benefit from the return of samples containing gas inclusions to Earth. In the following sections two nominal reference missions are identified: an atmospheric reference mission and a reference mission to the north polar dome for deep drilling, in order to define the more site-specific human-enabled mission activities necessary to sample the critical volatile records contained within the polar ice caps. Atmospheric reference mission activities are anticipated to be included in all human missions.
Nominal Atmospheric Human Science Reference Mission (HSRM)Science Goals And ApproachThe nominal atmospheric reference mission would address the goals described in Appendix B: “Quantitative understanding of atmospheric processes” and “Microclimates.” These goals would require similar investigations, however a microclimate objective would be more specific, requiring additional planning to optimize site selection for meteorological stations, and time-phasing of investigations relative to relevant seasonal cycles. Site selection considerations are described under “location” below. A proposed baseline is one central station (could be close to hab, but see constraints on fetch under location section) plus remote stations either to broadly characterize the region (co-sited with major geology/biology investigations) or arranged to give three-dimensional information on specific flows associated with microclimate. The microclimate objective would also require (a) reference meteorological station(s) to provide regional context. The HSRM scientific capabilities are summarized in Table 7. Table 7. Proposed HSRM Atmospheric/Climate Goals and Approach
LocationSiting of a meteorological station as part of a global network or for regional context should consider an unobscured fetch in the direction of the prevailing wind. For boundary layer studies on Earth, 1km is considered the upwind requirement that would ensure the met station is representative of its surroundings. Booms holding sensors should be directed into the wind in order that the boom doesn't interfere with measurements. As the prevailing wind may not be known at the specific site, adjustment may be needed during the mission. Siting with respect to topography should take into consideration phenomena such as katabatic flows, gravity waves, and cloud base height. Downslope evolution is generally of interest, but cross slope information is useful for 3d information on eg gravity wave direction. Horizontal thermal gradients through eg albedo differences, can also drive local atmospheric circulations. | ||||||||||||||||||||