Equations of state and impactinduced shockwave attenuation on the moon
Abstract
Current equation of state formulations, used for finite difference cratering flow calculations, are cast into a framework permitting comparison of peak pressures attained upon impact of a sphere, with a halfspace, along the impact symmetry axis, to one dimensional impedance match solutions. On the basis of this formulation and application of thermochemical data, the regimes of melting and vaporization are examined. For the purpose of identifying material which will, upon isentropic release from the impactinduced shock state, result in a solid just brought to its melting point, i.e., incipiently melted (IM); completely melted (CM); just brought to its boiling point, i.e., incipiently vaporized (IV); and completely vaporized (CV) state, the pressures at which the critical isentropes intersect the Hugoniots of iron and gabbroic anorthosite (GA) are examined in detail. The latter rock type is assumed to be representative of the lunar highlands. The Hugoniot pressures, for which IM, CM, IV, and CV will occur upon isentropic expansion, are calculated to be 2.2, 2.6, 4.2, and 16.8 Mbar, respectively.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 1976
 Bibcode:
 1976STIN...7712987A
 Keywords:

 Equations Of State;
 Moon;
 Shock Wave Attenuation;
 Thermochemical Properties;
 Cratering;
 Finite Difference Theory;
 Gabbro;
 Hugoniot Equation Of State;
 Impact Loads;
 Lunar and Planetary Exploration