This paper describes a finite-element technique and modeling approach for an efficient and effective thermostructural analysis of structures with a reusable surface insulation (RSI) -type thermal protection system (TPS), with emphasis on its applications to current technological problems such as those of the Space Shuttle. Past modeling techniques and thermal analysis approaches are briefly discussed to illustrate current capabilities and analysis and modeling difficulties. The basic requirements for an effective unified thermal/structural approach are detailed. The finite-element formulations used are exact for steady-state heat transfer, and for transient heat transfer they can be implemented in conjunction with either an implicit algorithm or an explicit algorithm. Analysis of several wing configurations indicates that the explicit algorithm results are in good agreement, with only an insignificant loss in accuracy, when compared to results using an implicit algorithm. The technique and modeling procedures demonstrate that the approach can be applied and extended to efficiently and accurately analyze large sections of the shuttle wing configurations that are subjected to re-entry heating, with significant savings in model sizes and computational times.