Peaceful space facilities constitute an interdependent terrestrial-orbital infrastructure: satellites, ground stations, mission-control networks, user terminals, inter-satellite links, and software-dependent services. A malicious cyber operation directed at any one of these components may disrupt essential civilian functions far beyond the immediate target. Yet a damaging cyber incident does not itself establish an internationally wrongful act of a state, and an internationally wrongful act does not necessarily constitute a prohibited use of force or an armed attack. This article develops a sequential doctrinal framework for evaluating state responsibility for cyber operations against peaceful space facilities under the United Nations Charter, the 1967 Outer Space Treaty, and the law of state responsibility. Its method is qualitative legal analysis of primary instruments, current United Nations materials and peer-reviewed scholarship published principally in 2024–2026, supplemented by carefully labelled hypothetical scenarios. It distinguishes technical attribution, legal attribution, the content and breach of primary obligations, injury and reparation, and the independent conditions for lawful responses. It argues that Article III of the Outer Space Treaty confirms the applicability of the Charter in the space domain, whereas Articles VI–IX add distinctive but non-identical obligations concerning national space activities, launch-related liability, jurisdiction and control, and due regard. These rules should not be collapsed into a blanket presumption that a state is responsible for every cyberattack by a private actor connected to its territory. An effects-sensitive analysis can identify conduct potentially falling under Article 2(4), while the more demanding armed-attack inquiry governing Article 51 requires a separate assessment of scale, effects, necessity and proportionality. The proposed evidentiary and institutional approach prioritizes timely incident preservation, reasoned legal attribution, consultations and reversible non-forcible measures. It addresses the legal uncertainty surrounding non-destructive interference, due diligence and the reach of the specialized space-liability regime without treating contested interpretations as settled law.