# Secure and Transparent Space Exploration Data Management Using a Hybrid Blockchain Model
## 4 Implementation and Experimental Analysis  
### Implementation Environment  
To verify the effectiveness of the hybrid blockchain-based space exploration data management model, an experimental environment was established, and performance was evaluated. The spacewalk dataset used in this study was obtained from NASA's public data portal, containing extravehicular activity data from the United States and Russia [18]. These data entries served as representative records for testing both public and private data handling within the proposed architecture.  
The public blockchain component was implemented using the Ethereum Linea Testnet. Ethereum was selected due to its robust smart contract ecosystem and its compatibility with zero-knowledge proof frameworks. Linea Testnet, in particular, supports zkEVM operations, enabling cost-effective validation of cryptographic proofs on-chain. It ensures transparency and verifiability for non-sensitive mission data.  
For the private blockchain, we adopted Hyperledger Fabric, a permissioned blockchain platform designed for enterprise-grade data management. Hyperledger Fabric offers modular components, fine-grained access control policies, and a Practical Byzantine Fault Tolerance consensus algorithm, allowing for high-speed, low-latency transaction processing. This makes it suitable for managing sensitive data, such as astronaut health logs and proprietary mission protocols, with strict confidentiality.  
To enable interoperability between the two blockchains, we employed Chainlink's Cross-Chain Interoperability Protocol. Unlike traditional oracle-based systems that depend on a centralized data relay, CCIP enables secure, event-driven cross-chain communication through smart contracts. It provides cryptographic assurances for message delivery and minimizes synchronization delays, ensuring real-time propagation of integrity proofs such as hashes and ZKPs between chains.  
The smart contracts used in this implementation were written in Solidity and deployed using Remix IDE and Truffle. Ethereum nodes were emulated using Ganache for development and testing, while the Hyperledger Fabric environment was constructed using Docker containers to simulate a multi-organization network with role-based permissions and certificate-based identity verification.  
This configuration allowed us to assess the system's behavior in terms of data integrity, access control, and performance under a realistic yet controlled experimental setup. The implementation environment, including blockchain platforms, development tools, and node configurations, is summarized in Table 2.  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Category** & **Details** \\ \hline Public Blockchain & Linea Testnet \\ \hline Private Blockchain & Hyperledger Fabric [19] \\ \hline Blockchain Interconnection & Oraclize and Chainlink \\ \hline Smart Contracts & Solidity-based smart contracts \\ \hline Node Configuration & 3 Ethereum full nodes, 2 Hyperledger Fabric peer nodes \\ \hline Development \& Testing Tools & Remix IDE, Truffle, Ganache, Docker-based Hyperledger Fabric \\ \hline \hline \end{tabular}
\end{table}
Table 2: Implementation environment of a hybrid blockchain system.