Mars Global Reference Atmospheric Model Mars Gram Version 38 Users Guide

Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8 is presented and its new features are discussed. Mars-GRAM uses new values of planetary reference ellipsoid radii, gravity term, and rotation rate (consistent with current JPL values) and includes centrifugal effects on gravity. The model now uses NASA Ames Global Circulation Model low resolution topography. Curvature corrections are applied to winds and limits based on speed of sound are applied. Altitude of the F1 ionization peak and density scale height, including effects of change of molecular weight with altitude are computed. A check is performed to disallow temperatures below CO2 sublimination. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and running the program. Sample input and output are provided. An example of incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code is also given.Justus, C. G. and James, B. F.Marshall Space Flight CenterMARS (PLANET); MARS ATMOSPHERE; ATMOSPHERIC TEMPERATURE; ATMOSPHERIC MODELS; ATMOSPHERIC DENSITY; SUBROUTINES; USER MANUALS (COMPUTER PROGRAMS); COMPUTER AIDED TOMOGRAPHY; TOPOGRAPHY