Abstract— In Earth observation (EO) applications, the new trend moves toward using small satellites architectures like constellations and swarms. These architectures are low-cost, simple, and have relatively short development time. The Blockchain topology proved high efficiency in terrestrial systems due to its reliability, security, and latency reduction. In mobile satellite communication system, Blockchain represents a revolution in how to validate data integrity and create secure prioritized data exchange. In this paper, we present a survey about the adoption of Blockchain in space industry and its applications. This study presents challenges, suggested solutions and open research points in building satellite systems based on blockchain.