The rapid advancement of satellite technology has transformed how Earth receives critical scientificandoperational data. However, the process of transmitting information from satellites to ground stations involves multiplerelaypoints, which creates significant risks of data tampering, unauthorized modification, and communicationdisruption.Traditional communication protocols, though reliable to a certain extent, are not designed to guarantee end-to-enddataauthenticity and traceability across all stages of transmission. This creates vulnerabilities that can directly impact missionsuccess, scientific accuracy, and the overall safety of space operations. This project, titled “Trusted Data Relay fromSpacetoEarth using Custom Blockchain Ledger,” proposes a novel approach that integrates blockchain technology into multi-layerspace communication systems. The work involves designing and implementing a custom blockchain ledger fromscratchinPython, ensuring that every piece of data generated at the satellite level is validated, recorded, and securely transmittedthrough the relay and processing layers until it reaches the application stage. By embedding real-time hash validationandtamper detection mechanisms at each layer, the system guarantees that even the smallest alteration indatacanbeimmediately identified and rejected. Beyond technical implementation, this project also emphasizes the educational dimensionof blockchain in aerospace communication. The solution is designed to be lightweight, locally deployable, and suitablefordemonstration on student laptops, thereby bridging the gap between theoretical knowledge and practical experimentation. Toachieve this, the blockchain is customized with a simplified block structure and consensus mechanismthat alignwithbothmission-critical reliability and academic accessibility. The system will also simulate realistic satellite telemetry data, networkdelays, and communication conditions, making it an effective learning platform in addition to being a secure communicationmodelKeywords: Blockchain Ledger; Space Communication; Data Integrity; Secure Transmission; Tamper Detection; Multi-layerNetwork; Proof of Work; Satellite Telemetry; Distributed Systems; Aerospace Security