Space is no longer a distant frontier. It is critical infrastructure, and it is far more fragile than most of us realise. In this timely session, Katherine Courtney, former CEO of the UK Space Agency and Chair of the Global Network on Sustainability in Space, explores how rapid growth in satellites, debris, and geopolitical competition is putting vital systems at risk. From GPS and communications to aviation, finance, and national security, our reliance on space has never been greater, yet our resilience to disruption is alarmingly low. Drawing on current global developments, including new national space strategies, mounting pressure for updated international treaties, and growing concern over space traffic management and space weather, Katherine shows why sustainability in orbit has become an urgent global challenge. This talk offers a clear, compelling case for why governments, industry, and technologists must act now to keep space safe, secure, and sustainable, before the consequences are felt back on Earth.