  We provide detailed background, theoretical and practical, on the specific
heat cp of minerals and mixtures thereof, 'astro-materials', as well as
background information on common minerals and other relevant solid substances
found on the surfaces of solar system bodies. Furthermore, we demonstrate how
to use specific heat and composition data for lunar samples and meteorites as
well as a new database of endmember mineral heat capacities (the result of an
extensive literature review) to construct reference models for the isobaric
specific heat cP as a function of temperature for common solar system
materials. Using a (generally linear) mixing model for the specific heat of
minerals allows extrapolation of the available data to very low and very high
temperatures, such that models cover the temperature range between 10 and 1000
K at least (and pressures from zero up to several kbars). We describe a
procedure to estimate cp(T) for virtually any solid solar system material with
a known mineral composition, e.g., model specific heat as a function of
temperature for a number of typical meteorite classes with known mineralogical
compositions. We present, as examples, the cp(T) curves of a number of
well-described laboratory regolith analogues, as well as for planetary ices and
'tholins' in the outer solar system. Part II will review and present the heat
capacity database for minerals and compounds and part III is going to cover
applications, standard reference compositions, cp(T) curves and a comparison
with new and literature experimental data.
