This map marks the start of a number of maps related to the BattleTech science fiction setting, from the miniatures game, novel line and video game of the same name and the MechWarrior series of video games. You can find out more about the setting here.

These series of maps depict known space as it stands in the year 3025, after the Third Succession War. This is the time period of the “classic” BattleTech setting and approximately the setting of the recent video games BattleTech and MechWarrior 5: Mercenaries.

The approximate boundaries of explored space in 3025, depicting the Inner Sphere, Periphery and Deep Periphery. Please click for a larger version.

During the past nine centuries of interstellar exploration and settlement, humanity has expanded across a region roughly circular* in shape, approximately four thousand light-years across and centred on Terra, humanity’s ancestral homeworld. This region is vast and crowded; more than 50 million stars are located in this volume of space, less than three thousand of which have been settled by humanity and only a few multiples of that have even been visited by spacecraft. Of course, this area is infinitesimal when compared to the remainder of the Milky Way Galaxy; less than 4% of its width has been explored by humans.

The exploration of this volume of space was undertaken by several bodies, most notably the Terran Hegemony, the Rim Worlds Republic, and the Star League which they were both part of. Survey ships struck out on perilous journeys far beyond the rim of settled space in search of worlds suitable for terraforming, if not the rare jewels of worlds already suitable for colonisation. Not all these ships returned; jump technology was not always certain and sometimes, after hundreds of jumps carrying ships far out of communications range of settled space, their recharging systems would fail, leaving ships stranded with no way of getting home. Exploration was thus perilous.

After the fall of the Star League in 2781 and the beginnings of the Succession Wars, exploration became of less interest to the major powers. There were more than enough worlds to be dealing with already, most of them not in any imminent danger of overpopulation, and the impetus for costly, dangerous journeys was reduced. The age of exploration did not completely come to an end – ComStar, in particular, maintains an exploration arm, and the private firm Interstellar Expeditions maintains some long-range surveys – but it did slow dramatically.

Divisions of Known Space

Known space is divided into three distinct regions, defined as follows:

  • The Inner Sphere: the region of space surrounding Terra and extending out roughly 400 light-years anti-spinward, 600 light-years spinward and approximately 400 light-years both coreward and rimward. The Inner Sphere is dominated by the five Successor States: the Lyran Commonwealth, Draconis Combine, Federated Suns, Capellan Confederation and Free Worlds League. This area of space is extremely densely populated, with over 1,900 settled planets located within roughly 600 light-years of Terra.
  • The Periphery: the region of space located immediately around the Inner Sphere, extending from roughly 600 out to around 800 light-years from Terra. The Periphery is dominated by several powers – the Magistracy of Canopus, the Taurian Concordat and Outworlds Alliance most notably – as well as a vast array of independent worlds in regions such as the Outworlds Wastes and the Rimward Frontier. The Periphery’s far frontier is ill-defined, but roughly runs along the Aquila Rift, Chameleon Nebula, Gum Nebula, Orion Rift and Perseus-Cepherus Cloud Complex.
  • The Deep Periphery: this utterly vast but incredibly lightly-settled region surrounds the Inner Sphere and Periphery, extending out from around 800 light-years to a staggering distance of over 1,900 light-years from Terra. The Deep Periphery lacks almost any polities of note, bar the Hanseatic League to coreward, contact with which is sporadic and vague, and minor powers like the New Delphi Compact and the Axumite Providence. Traversing the Deep Periphery, even to known destinations, is hazardous due to the vast distances involved (a trip from Terra to Leviathan’s Rest and back would entail no less than 128 jumps, most of them requiring recharging in unsettled systems) and the lack of safe harbours for resupply.
  • Unexplored Space: obviously constituting the majority of the galaxy (more than 96% of it). Exploration corewards, past the Caliban Nebula, has been discouraged by rising radiation levels the closer one gets to the galactic core, although some believe more life-bearing worlds could be found before these levels became too hazardous for human life. Exploration rimwards has been discouraged by a gradual thinning of the galactic disk and life-bearing planets becoming further and further apart. Again, however, several thousand light-years of space are believed to be viable before that point is reached. Truth be told, exploration beyond known space has been discouraged by cost, the danger, the relative irreplaceability of modern JumpShips and the simple lack of need, with some systems even within the Inner Sphere itself still not being fully charted as yet.

* Maps in the BattleTech universe are curiously two-dimensional, depicting events taking place on an approximately 2D plane of the galaxy centred on Sol. Stars “above” and “below” the map appear to have not been settled in significant numbers, and well-known stars above and below the galactic plane (such as, for example, Polaris) are not listed, or have been moved. In other cases, real, named stars are not in their correct spatial relations to Earth (Terra) or one another. For reasons of sanity, it is best to assume that BattleTech takes place in a parallel universe version of the Milky Way where the major powers have chosen not to settle worlds above or below the galactic plane and the Inner “Sphere” is actually more pancake-shaped.

Next time we will take a closer look at the Inner Sphere itself.

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