A12. Complex Layout Score (CLS)
What the CLS is for
The Complex Layout Score (CLS) is a practical way to compare contiguous pressurized habitat layouts on Mars (or other planetary settlements) using one structured, transparent system. It focuses on how well a single/double-storey, internally connected complex is planned — as a network of building nodes and street links — so that people can live and work in shirt-sleeve conditions without constant EVA or tracking Martian dust through daily life. It does not look at wider site layout (i.e. where to put the rocket operations and solar farm), or internal pressurized zones layout (i.e. where to put the kitchen).
Threshold philosophy: A ≥10,000 m² pressurized complex is treated as the first meaningful civic scale on Mars. Below this, outposts behave like individual habs (or hab pairs / triplets), vehicles or field labs. At and above 10,000 m², “normal life” becomes possible — multiple functional “buildings”, internal circulation without EVA, redundancy, fire/pressure sectoring, and growth.
Scope (what it does / does not do)
CLS evaluates the layout of larger sets of connected pressurized buildings nodes and street links, not the fit-out within a single building or street.
In scope: the building-scale graph of a complex—how pressurized “building nodes” and “street links” connect; location of bulkheads and airlocks; pressure sectors; haven placement; utility loop topology; heavy-machinery access outside the envelope; planned reserve land inside the site.
Out of scope: furniture plans, cabin design, wall assemblies, HVAC sizing, laboratory layouts, or farming modalities inside a room (those are separate, local optimizations.) Also <10,000 m² pressurized complex can be evaluated by the CLS, but the diagnostic is not optimized for that size of habitation system.
Key Concepts & Terms
Node: a primary independent pressurized space with external walls (e.g., a barn/hall, med bay, workshop).
Link: a pressurized corridor/tunnel joining two or more nodes.
Link-door: the doorway/airlock where a node meets a link.
Node-door: a doorway/airlock directly between two nodes, with no link.
Bulkhead: a sealable door line intended for pressure/fire isolation.
Compartment: the area isolated when bulkheads on its perimeter are closed.
Haven: a hardened refuge reachable quickly from occupied spaces.
Dirty vs Clean zones: “dirty” = garages, ISRU, fab; “clean” = sleep, med, mess, admin—kept separated by bulkheads. Dirty zones get dusty, whereas clean zones don’t.
ROW (Right-of-Way): a platted corridor reserved for future links or service alleys.
Surface access graph: the external routes a rover/crane can drive to reach any node for construction/maintenance.
Hard Gates (pass/fail checks)
CLS starts with a few non-negotiables. Failing any gate means the layout is not acceptable (score can be reported as 0, with an optional “provisional” breakdown). These gates formalize the minimum for “shirt-sleeves city life” under Martian risk.
Connected & sized: one internally connected complex, ≥10,000 m² pressurized area.
Safe access to refuge: every occupied node has ≥2 edge-disjoint routes to a haven within a set time (e.g., 60 s).
Sectoring: with bulkheads closed, no sealed pressure compartment exceeds the target size (e.g., ≤1,500 m²).
Dirty↔Clean discipline: all shortest paths between dirty and clean nodes include ≥1 bulkhead/interlock.
Shielding minima: HAB/MED nodes meet the design areal density target for radiation protection.
The Eight Elements (how CLS scores)
Each element is scored 0–1 and combined with fixed weights to make CLS-100 (0–100). You don’t need the algebra to use the system; think of each element as a dial. Tip: When presenting results, show both the single number and an 8-spoke “radar” chart so strengths/weaknesses are visible. Weighting shown in brackets.
Safety & Resilience (Weight = 0.33) - Do people have fast, redundant ways to safe havens? Are pressure/fire consequences limited? Are dirty and clean areas properly interlocked? Is basic shielding in place? Do routes and utilities gracefully degrade under failures?
Flow & Operations (Weight = 0.18) - How long do typical trips take? Are there chokepoints? Are there two practical routes for critical operations (not just one)? Are bulkhead crossings kept to a sensible minimum in day-to-day movement?
Plan & Envelope (0.08) - Is the network compact without being cramped? Is link length proportional to area (no gratuitous corridors)? Is there space left inside the site for future domes/parks/industry (not wall-to-wall build-out)? Are reserve lots real (wide enough, road-served, with utility stubs)?
Mass Efficiency (proxy) (0.08) - A simple penalty for geometric complexity: too many joints, bends, 4-way junctions, curved pieces; and civil works like bridges/underpasses for access. It rewards straight, modular, T-junction-heavy geometry.
Construction & Maintenance (0.08) - Are utility runs accessible with isolation points spaced sensibly? Are junctions serviceable? Are nodes/links standardized into a small family of repeatable parts with toleranced shims? Can heavy machinery reach most nodes from outside without heroic works?
Expandability (0.08) - Can you attach more modules easily? Build new phases while staying online? Are there reserved corridors for future cross-ties and service alleys? Are utilities pre-stubbed for dual/tri loops? Can today’s bays be merged later to form large internal lots?
Habitability (0.09) - Are commons close to where people sleep? Are quiet and noisy uses buffered? Is there daylight or a certified circadian-light program in living/commons?
Environmental & Energy (0.08) - Are hot uses separated and on independent HWAC? Do most nodes have two independent feeds for power/air/water (three for criticals at higher independence levels)? Are external suit/rover airlocks sensibly few and well-placed?
Future-Proofing (designed in—not an afterthought)
CLS explicitly prices option value and path to the next stage:
Reserved space inside the hull: target a sensible share (e.g., ~15%) of platted internal reserves large enough for a future park dome or industrial hall; each lot must have width, road access, and utility stubs.
Transformability: how close today’s graph is to the next canonical topology (e.g., spine→ring, ring→mesh), including pre-stubbed cross-links.
Low-disruption upgrades: what fraction of floor area must go offline to reach the next stage.
Mergeability: how easily you can remove/recombine bays later to create big interior lots.
ROW coverage: reserved corridors for future ties and driveable service alleys.
Utility readiness: space and terminations for additional loops and sectionalizers.
Adjustments (guardrails against brittle designs)
Two light global adjustments keep designs honest:
Path-Dependence Risk (−0…−5): small deductions for decisions that trap you in a local maximum (e.g., long cul-de-sacs, “independent” utility loops co-routed in the same trench, blocked ROWs, doors that cannot be upgraded to bulkheads, bays off the base grid).
Over-pack penalty (−3 / −6): if the pressurized footprint consumes ~all of the site hull (no internal reserves), we deduct a few points. Compact but evolvable is the goal.
CLS also gives half-credit for roughed-in but unopened features (capped cross-links, empty conduits, marked reserve lots). You get rewarded for foresight without paying full complexity now.
How to use CLS (practical workflow)
Collect a minimal data sheet from the plan
List of nodes (area, function tag, clean/dirty, shielding tag, haven yes/no).
List of links/doors (length, width, bulkhead or not, geometry type, capacity).
Utility loop diagram (feeds, sectionalizers/valves).
Heavy-access plan (driveable routes, bridges/underpasses).
Site plan with reserved lots and ROWs.
Run gates → compute elements
If a gate fails (e.g., no redundant egress), the design is not acceptable. If it passes, compute the eight elements (0–1 each) and the overall CLS-100.
Report like this
CLS-100 and 8-element radar; list any gate margins (e.g., biggest compartment size).
A Future Space Index (Plan & Expandability sub-scores that capture reserves, ROWs, transformability).
A Pareto view plotting CLS-100 vs m² per tonne (or m²/kt) so mass and quality are both visible.
A one-page acceptance test: egress drill, single-edge failure drill, heavy-access coverage, utility loop isolation test.
Decide: Prefer designs that meet gates, land in your CLS target band for the current independence level, and show low distance-to-next-stage (good future-proofing).
Reading scores (sanity bands)
≤29: fails gates / unsafe.
30–49: minimally compliant; brittle.
50–64: baseline functional.
65–79: good / robust.
80–89: excellent / mission-ready.
90+: state-of-the-art (redundant people & utilities loops, sectoring, reserves, live expansion).
Known limits (use CLS wisely)
CLS is a layout score; it doesn’t rate cabin ergonomics, lab workflows, or crop choices.
It uses proxies (e.g., bends/junctions) for mass/maintainability; if your structural system prefers curves, document that in the narrative.
It scores a snapshot; pair it with a short set of scenario drills (e.g., breach + power transient) to check edge cases.
Always report assumptions (e.g., walking speed, egress time, shielding targets) alongside the score.