Tech Level 5 (circa 1930): Sealed and conditioned cities become possible. While at tech level 4 sealed and conditioned dwellings are possible, this technology has expanded to include an entire city as a unit. Multistory structures over 100 meters in height appear (skyscrapers).
Tech Level 6 (circa 1950): Building an entire city in a jungle becomes feasible. Skyscrapers become commonplace.
Tech Level 7 (circa1970): Civil engineering advances enough to make entire underground cities possible.
Tech Level 8 (circa 1990): Orbital settlements (an orbital station (not closed-cycle)) with a permanent population of up to 100 become possible. An early form of wide-scale weather control is introduced. Semireliable seismic quake prediction appears.
Tech Level 9 (circa 2010): Orbital cities (a closed-cycle orbital station) with a permanent population of 1000 or more are introduced. Large, totally self-contained cities (arcologies) become possible.
Tech Level 10 (circa 2100): Undersea and under-ice cities become practical. Early seismic quake control appears.
Tech Level 11: Structures whose design relies upon a gravitic supplement appear. These structures would collapse without the permanent aid of their gravitic support.
Tech Level 12: Major terraforming projects covering thousands of square kilometers become commonplace. Significant advances in global weather control help make such terraforming projects possible. Massive gravitic structures that can freely move about appear.
Tech Level 13: Entire cities supported by gravities appear (populations in excess of one million). Although such cities are stationary (i.e., nonmobile), they can be suspended in the sky at altitudes of up to one kilometer.
Tech Level 14: Gravitic-supported cities that can move about are introduced. Such cities can now reach altitudes of over 10 kilometers.
Tech Level 15: Gravitic cities can now reach orbit on their own. Complex terraforming involving an entire hemisphere becomes commonplace Reliable seismic quake control is also common.
Above the Imperium's highest tech level:
Tech Level 16: Global terraforming becomes commonplace, allowing substantial improvements in a world with an unfavorable global environment. For example, transforming a world with an insidious atmosphere to a world with a standard atmosphere is global terraforming
Beyond Tech Level 16: Total terraforming appears at tech level 17 and beyond. Total terraforming involves complete transformation of a world's basic environment to a radically different basic environment of one's choosing For example, transforming a barren vacuum world to a lush, rich world with a dense atmosphere is total terraforming. At extremely high tech levels, moving entire planets about, even through jump space, becomes possible.