NexaSphere is a Horizon Europe research and innovation project focused on designing and validating a unified three-dimensional (3D) communication network. It explores the integration of terrestrial (TN), non-terrestrial (NTN), and aerial systems to support future mobility and connectivity needs across aviation, automotive, and rail sectors. The project investigates architecture, orchestration, and technology components, with validation carried out through three domain-specific proof-of-concept demonstrations.