Building on historical lessons for space governance, urgent action is needed to address escalating threats. Today, we face a dangerous gap in space security: our deterrence frameworks are obsolete for borderless domains, like space. Meanwhile, U.S. intelligence warns that Russia’s “satellite inspectors” may be prototype anti-satellite (ASAT) weapons, and Russian electronic warfare systems continue to jam Global Navigational Satellite Systems (GNSS) signals across Eastern Europe — sometimes disrupting civilian aviation hundreds of miles from Ukraine. As seen in one of the worst episodes of satellite navigation interference ever, a 63-hour-long attack on GNSS signals occurred in March 2024, affecting more than 1,600 passenger planes. These are not anomalies but systemic failures of outdated frameworks for deterrence and arms control in these borderless warfighting domains.