Experience with free-flying space payloads in the current era of reduced budgets has led to a continuing need for an easier-to-use and more cost-effective capability for spacecraft thermal analyses. Preliminary thermal design of the MSX spacecraft has been developed using an 80386-based MS-DOS microcomputer. Geometry generation is performed using VIEWI and VIEWG1. These programs provide both an interactive geometry editor and a graphical representation of the current spacecraft geometry. The output of VIEWI is converted to a SSPTA2 geometry input file. SSPTA, a software package that simplifies the procedures for conducting sophisticated thermal analyses of orbiting payloads, consists of CONSHAD, a view factor calculation program, SCRIPTF, a radiation conductance calculation program, ORBITAL, a satellite orbital heat flux program, and ABSORB, a program to calculate absorbed power. SSPTA output can be converted into a SINDA3 input file. SINDA is an industry-standard finite differencing analysis program which calculates steady state and transient temperatures. The numerical output of SSPTA and SINDA can then be plotted using various plotting packages. The color contouring features of ALGOR4 are used to plot temperature contours and heat flux contours.