The rapid advancement of satellite technology has transformed how Earth receives critical scientific andoperationaldata. However, the process of transmitting information from satellites to ground stations involves multiple relay points, whichcreates significant risks of data tampering, unauthorized modification, and communication disruption. Traditional communicationprotocols, though reliable to a certain extent, are not designed to guarantee end-to-end data authenticity and traceabilityacrossallstages of transmission. This creates vulnerabilities that can directly impact mission success, scientific accuracy, andtheoverallsafety of space operations.This project, titled “Trusted Data Relay from Space to Earth using CustomBlockchainLedger,”proposes a novel approach that integrates blockchain technology into multi-layer space communication systems. The workinvolvesdesigning and implementing a custom blockchain ledger from scratch in Python, ensuring that every piece of data generatedatthesatellite level is validated, recorded, and securely transmitted through the relay and processing layers until it reachestheapplication stage. By embedding real-time hash validation and tamper detection mechanisms at each layer, the systemguaranteesthat even the smallest alteration in data can be immediately identified and rejected. Beyond technical implementation, this project also emphasizes the educational dimension of blockchaininaerospacecommunication. The solution is designed to be lightweight, locally deployable, and suitable for demonstration onstudent laptops,thereby bridging the gap between theoretical knowledge and practical experimentation. To achieve this, the blockchainiscustomized with a simplified block structure and consensus mechanism that align with both mission-critical reliabilityandacademic accessibility. The system will also simulate realistic satellite telemetry data, network delays, and communicationconditions, making it an effective learning platform in addition to being a secure communication model. Keywords:Blockchain Ledger; Space Communication; Data Integrity; Secure Transmission; Tamper Detection; Multi-layerNetwork; Proof of Work; Satellite Telemetry; Distributed Systems; Aerospace Security.