Sustainability or Survivability? Eliminating the Need to Choose in LEO Satellite Constellations

LEO Satellite Networks (LSNs) are revolutionizing global connectivity, but their reliance on tens of thousands of satellites raises pressing concerns over sustainability and survivability. In this work, we argue that the inefficiencies in LSN designs stem from ignoring the strong spatiotemporal structure of Internet traffic demand (which impacts sustainability) and the physical realities of the near-Earth space environment (which affects survivability). We propose a novel design approach based on sun-synchronous (SS) orbits called SS-plane, which aligns satellite coverage with the Earth's diurnal cycle. We demonstrate that SS-plane constellations can reduce the number of satellites required by up to an order of magnitude and cut radiation exposure by ~23% compared to traditional Walker-delta constellations. These findings suggest a paradigm shift in LSN research from large, disposable megaconstellations to more sustainable, targeted LEO constellations.