  As an end-member of terrestrial planet formation, Mercury holds unique clues
about the original distribution of elements in the earliest stages of solar
system development and how planets and exoplanets form and evolve in close
proximity to their host stars. This Mercury Lander mission concept enables in
situ surface measurements that address several fundamental science questions
raised by MESSENGER's pioneering exploration of Mercury. Such measurements are
needed to understand Mercury's unique mineralogy and geochemistry; to
characterize the proportionally massive core's structure; to measure the
planet's active and ancient magnetic fields at the surface; to investigate the
processes that alter the surface and produce the exosphere; and to provide
ground truth for current and future remote datasets. NASA's Planetary Mission
Concept Studies program awarded this study to evaluate the feasibility of
accomplishing transformative science through a New-Frontiers-class, landed
mission to Mercury in the next decade. The resulting mission concept achieves
one full Mercury year (~88 Earth days) of surface operations with an ambitious,
high-heritage, landed science payload, corresponding well with the New
Frontiers mission framework. The 11-instrument science payload is delivered to
a landing site within Mercury's widely distributed low-reflectance material,
and addresses science goals and objectives encompassing geochemistry,
geophysics, the Mercury space environment, and surface geology. This mission
concept is meant to be representative of any scientific landed mission to
Mercury; alternate payload implementations and landing locations would be
viable and compelling for a future landed Mercury mission.
