Figure 1. Crucial scientific measurements for understanding the Mars system require access to and interaction with the Mars surface. Access to and interaction with rocks and ices is needed for measurements of texture, chemistry, mineralogy, isotopes at organics content at sub-centimeter scale. Landed measurements are required for boundary layer winds and measurements of exchanging gases (e.g., CH4, H2) at the surface-atmosphere boundary. Priority measurements of the subsurface that can only be accomplished with landers include sounding for water, heat flow measurement, and detecting Mars quakes to resolve subsurface structure at regional scales.
Image credit: Keck Institute for Space Studies / Chuck Carter.