What defines the architectural concept of a hollowed-out asteroid city theorized by Rochester researchers?

Carving out vast, sheltered caverns entirely shielded by rock mass

The concept of the hollowed-out asteroid city moves away from exterior construction, which necessitates transporting massive amounts of shielding material across vast interplanetary distances. Instead, researchers from Rochester theorized utilizing very large asteroids (a kilometer or more in diameter) as natural shells. The architecture involves extensive interior excavation to create vast, sheltered caverns. These interior spaces would be large enough to host functional small cities under artificial illumination, with the critical advantage that they are entirely shielded by meters of the asteroid's inherent solid rock mass. This approach inherently solves both radiation protection and thermal stability requirements by using the existing mass.