<p>Spectral markers are materials with a characteristic emission spectrum, which are added to a spacecraft structure, e.g., a satellite. During an atmospheric re-entry, the marker is released and its radiation can be detected by appropriate instruments. This allows to identify breakup events and to assess the spacecraft’s demise behavior during an observation campaign. In this paper, we study various compounds to select suitable materials for future integration as spectral markers. Six material candidates were tested in the plasma wind tunnel PWK4 at the Institute of Space Systems at the University of Stuttgart. Powdered material was encased in an epoxy resin matrix and mounted to a water-cooled sample holder. Spectra, temperature, and visual data were recorded throughout testing. Lanthanum acetate, lanthanum oxide, and lanthanum oxalate are considered non-viable marker materials. Lanthanum hexaboride features strong atomic lines of lanthanum as well as molecular bands of LaO and BO in a wide wavelength range within the visible and near-infrared (370–820 nm). Rubidium chloride features very strong atomic lines of Rb in the NIR (780–790 nm), well separated from the atomic radiation of air species. Strontium features moderately strong atomic lines. In conclusion, rubidium chloride and lanthanum hexaboride are considered promising marker materials for re-entry event identification through spectroscopic observation.</p>