The objective of this paper is to estimate heat fluxes on the surface of advanced materials with known thermal and thermokinetic properties using the approach based on inverse methods. In many practical situations it is impossible to measure directly heat fluxes on the surfaces of analyzed composite structures (in particular a thermal protection systems (TPS) of spacecraft) especially in the case of thermokinetic processes inside materials. The only way that can often be used to overcome these difficulties is indirect measurements. This type of measurements is usually formulated as the solution of inverse heat transfer problems. By solving such inverse problems, the boundary conditions and unsteady temperature distribution are reconstructed using interior temperature measurements in structures. Such problems are ill-posed in mathematical sense and their main feature shows itself in the solution instabilities. The general method of iterative regularization is concerned with application to the estimation of external heat flux for thermal protection of spacecraft. (C) 2016 Elsevier Ltd. All rights reserved.