Where to Build: Multi-Objective Analysis Reveals Optimal Hub and Depot Locations

Orbital location selection is one of the most consequential decisions for Dyson swarm construction. We built a multi-objective Monte Carlo trade model to compare 8 candidate locations across cost, risk, and capability dimensions.

The Questions

Two related research questions drove this analysis:

• RQ-1-19: Where should the Assembly Node Hub be located?
• RQ-1-36: Where should logistics depots be positioned?

These decisions are coupled—hub location affects depot requirements, and depot placement constrains operational flexibility.

The Candidates

We evaluated 8 orbital locations spanning cislunar space to Mercury orbit:

Location	Distance	Solar Flux	Delta-V from Earth
Lunar NRHO	0.0026 AU	1,361 W/m²	3.5 km/s
Sun-Earth L1	1.0 AU	1,361 W/m²	4.0 km/s
Sun-Earth L4/L5	1.0 AU	1,361 W/m²	4.5 km/s
Heliocentric 1.0 AU	1.0 AU	1,361 W/m²	4.0 km/s
Heliocentric 0.7 AU	0.7 AU	2,780 W/m²	6.0 km/s
Heliocentric 0.5 AU	0.5 AU	5,444 W/m²	8.0 km/s
Venus L4/L5	0.72 AU	2,620 W/m²	5.5 km/s
Sun-Mercury L1	0.39 AU	8,900 W/m²	12.0 km/s

The Key Finding: L4/L5 for Phase 1, Inner System for Phase 2

Sun-Earth L4/L5 provides the optimal balance for Phase 1 operations.

Objective	Winner	Why
Lowest Cost	Sun-Earth L1	Minimum delta-V from Earth
Highest Capability	0.7 AU Heliocentric	2× power density
Lowest Risk	Sun-Earth L4/L5	Gravitationally stable, proven thermal
Overall	Sun-Earth L4/L5	Best risk-adjusted performance

The Pareto Frontier

Multi-objective optimization reveals that no single location dominates across all criteria. The Pareto-optimal solutions are:

1. Sun-Earth L4/L5 - Best for risk-averse Phase 1
2. Heliocentric 0.7 AU - Best for power-optimized Phase 2
3. Lunar NRHO - Best for cislunar staging only

Mercury orbit (0.39 AU) falls off the Pareto frontier due to thermal management challenges that increase risk without proportionate capability gains.

The Thermal Cliff

The simulation reveals a critical threshold at 0.5 AU:

Distance	Radiator Requirement	Feasibility
>0.7 AU	~3,000 m²	Standard design
0.5-0.7 AU	~6,000 m²	Oversized radiators
<0.5 AU	>10,000 m²	Active cooling mandatory

Operations inside 0.5 AU require fundamental thermal architecture changes.

For Phase 1, staying outside this thermal cliff dramatically reduces risk.

Delta-V Budget Analysis

Round-trip mission costs from each depot location:

Depot Location	To Swarm (1 AU)	Round Trip	Tank Sizing
NRHO	3.5 km/s	7.0 km/s	Large
L4/L5	2.5 km/s	5.0 km/s	Moderate
0.7 AU	1.5 km/s	3.0 km/s	Small

L4/L5 provides excellent logistics efficiency—close enough to Earth for resupply, close enough to swarm for deployment.

The Two-Tier Architecture

Based on the analysis, we recommend:

Tier 1: Cislunar Staging (NRHO)

• Receives Earth-launched cargo
• Propellant depot for outbound tugs
• Human-accessible for crewed operations

Tier 2: Heliocentric Operations (L4/L5)

• Primary Assembly Hub location
• Swarm deployment staging
• Long-duration autonomous operations

This architecture:

• Keeps humans in cislunar space (safer, shorter rescue time)
• Positions manufacturing where solar power is reliable
• Minimizes total delta-V across the logistics chain

Communication Latency Analysis

Location	Earth Light-Time (one-way)	Impact
NRHO	1.3 seconds	Real-time control possible
L4/L5	8+ minutes	Requires autonomy
0.7 AU	4+ minutes	Requires autonomy

Any heliocentric location requires Level 3+ autonomy. The consensus specification already requires 30-day autonomous operation, so this constraint is already met.

Try It Yourself

We've published the interactive simulator so you can explore these trade-offs. Adjust candidate locations, feedstock sources, objective weights, and fleet parameters to see how recommendations change.

Methodology

The simulation uses:

• Hohmann transfer delta-V calculations for logistics costs
• Thermal equilibrium modeling for feasibility assessment
• Light-time calculations for communication latency
• 100 Monte Carlo runs with weighted multi-objective scoring

Results should be interpreted as relative comparisons between locations.

What's Next

This research answers RQ-1-19 and RQ-1-36, providing validated location recommendations for Phase 1. The L4/L5 baseline allows Phase 1 to proceed with known thermal technology while inner-system expansion remains an option for Phase 2.

Remaining work:

• Detailed swarm deployment geometry optimization
• Autonomy latency impact assessment
• Propellant logistics cost modeling for each architecture

---

Research Questions:

• RQ-1-19: Optimal orbital location for Assembly Hub
• RQ-1-36: Standard depot orbit selection

Interactive Tool: Orbital Trade Simulator