Quantum key distribution (QKD) leveraging satellites holds promise for global-scale secure communication. However, its practical deployment is threatened by the inherent predictability of satellite orbits, which exposes quantum channels to targeted eavesdropping attacks, compromising the physical-layer security guarantees of QKD. Through security analysis, we demonstrate that such attacks can drastically increase the quantum bit error rate (QBER) from 4.7% to 27.5%, effectively disrupting secure key generation. To address this fundamental vulnerability, we introduce a novel defense framework that integrates two strategies: (1) Stealthy Deployment, which obfuscates quantum satellites within massive LEO constellations to drastically increase an adversary’s search space, and (2) Dynamic Re-routing, which is an adaptive countermeasure that re-establishes QKD sessions via alternative paths upon eavesdropping detection. Evaluated through large-scale simulations incorporating real-world satellite data, our framework demonstrates up to a 90% improvement in key generation rate under active attack, ensuring robust and resilient satellite-based QKD without modifications to the underlying quantum hardware.