Shock standoffdistancefora sphereis calculated to examine thebehavioroftheexisting two-temperature model in theintermediate hypersonic e ow regime. Calculations are carried outforthreebinary scaling parametervalues, corresponding to nearly frozen, nonequilibrium, and nearly equilibrium e ows, respectively. The obtained shock standoff distances are compared with the experimental data obtained in a ballistic range. It is shown that the two-temperature model reproduces the shock standoff distances in the intermediate hypersonic e ows fairly well but tends to lose its accuracy where vibrational excitation occurs but chemical reactions are nearly frozen. Nomenclature M = collision partner in dissociation/recombination reactions p1 = static pressure in the test section, Pa q = power on the vibrational temperature in the dee nition of Ta, 0