Nomenclature*A = cross-sectional area A* = reference area, Eq. (20)heat of ablation or vaporization R = radius Re = Reynolds number t = time T = temperature, °K v = velocity a. = inverse scale height T = angle between flight path and horizontal e = function denoting second-order effects, Eq. (4) A = mean free path p -density or = entry parameter, Eq. (23) T = luminous efficiency factor TO = luminosity coefficient = ballistic parameter = 2wa s Subscripts B = body BL = boundary layer e = end of luminous flight p = photometric r = reflected 5 = stagnation SL = sea level 00 = conditions at entry