This paper aims at identifying retrofitting possibilities to incorporate existing spacecraft into a network of federated satellite systems. The paper presents a systematic review of possible retrofitting options, such as direct modifications including replacement and addition of interfaces, and indirect modifications through the addition of intermediary federated negotiators. The paper considers existing frequency regulations for the analysis in the technical domain, but does not take into consideration how complex or time-consuming any legislative changes might be. Although the paper concludes that direct modifications of existing satellites are nonfeasible from a technical point of view, it identifies a possible scenario of retrofitting b...