Colony Sustainability Score Calculator

Determine the long-term viability of an off-world settlement. This tool is inspired by the framework where Emanuel used the calculations below to assess colony potential.

Amortization Schedule (Projected Resource Depletion/Surplus)

Year	Starting Storage	Annual Net Change	Ending Storage

What is a Colony Sustainability Score?

The Colony Sustainability Score is a metric designed to provide a high-level assessment of a colony’s ability to survive and thrive over the long term without external support. It synthesizes key data points related to population, resource management, and environmental integrity into a single, understandable score. The higher the score, the more robust and self-sufficient the colony is projected to be.

This type of analysis is crucial for pioneers, planetary engineers, and interstellar governance bodies. Before committing to the immense undertaking of a new settlement, it’s vital to model its potential. The framework became famous when renowned strategist Emanuel used the calculations below to successfully predict the viability of the Kepler-186f settlement, averting a potential crisis. To learn more about viability metrics, see our guide on the Exoplanet Habitability Index.

Colony Sustainability Score Formula and Explanation

The calculation is divided into several intermediate steps to provide a comprehensive picture of the colony’s status.

Formulae Used:

1. Total Daily Consumption = Population * Consumption per Capita
2. Daily Net Resources = Daily Resource Production - Total Daily Consumption
3. Days of Autonomy = Total Resource Storage / Total Daily Consumption
4. Sustainability Score = ((Daily Net Resources / Population) * (Environmental Stability / 100)) * 100

The final score is a weighted value that considers the per-capita resource surplus, factored by the reliability of the systems that maintain the colony’s environment. A positive net resource is essential for growth, but it’s the stability of the environment that ensures long-term security. These factors are similar to those found in our Resource Scarcity Models guide.

Formula Variables

Variable	Meaning	Unit	Typical Range
Population	The number of colonists.	Individuals	100 – 1,000,000
Daily Resource Production	Combined output from hydroponics, water reclamation, etc.	Units/day	100 – 5,000,000
Consumption per Capita	Average resource needs per person.	Units/person/day	1.5 – 5
Environmental Stability	Integrity of life support, biosphere, and climate control.	Percentage (%)	50 – 100
Resource Storage	Total reserve capacity for essentials.	Units	10,000 – 100,000,000

Practical Examples

Example 1: Thriving New Colony

• Inputs: Population: 10,000, Daily Production: 25,000 units, Consumption: 2.2 units/person, Stability: 95%, Storage: 1,000,000 units
• Intermediate Results: Total Consumption: 22,000 units/day, Net Resources: +3,000 units/day, Autonomy: 45.5 days
• Sustainability Score: A high score, indicating a healthy, growing colony with a solid resource buffer and reliable systems.

Example 2: Struggling Outpost

• Inputs: Population: 1,500, Daily Production: 3,000 units, Consumption: 2.5 units/person, Stability: 70%, Storage: 50,000 units
• Intermediate Results: Total Consumption: 3,750 units/day, Net Resources: -750 units/day, Autonomy: 13.3 days
• Sustainability Score: A very low, likely negative score, signaling a critical resource deficit that threatens the colony’s immediate survival. Immediate action or resupply is required. This scenario highlights the importance of efficient Life Support System Efficiency.

How to Use This Colony Sustainability Score Calculator

1. Enter Population Data: Start by inputting the total number of colonists.
2. Input Resource Metrics: Provide the total daily resource production in standard units, along with the average daily consumption per person.
3. Set Environmental Stability: Estimate the percentage of reliability for your colony’s life support and environmental systems. 100% is perfect, while lower values represent higher risk.
4. Specify Storage Capacity: Enter the total number of resource units the colony can hold in reserve.
5. Analyze the Results: The calculator will instantly display the primary Sustainability Score. Review the intermediate values (Net Resources, Consumption, Autonomy) to understand the factors contributing to the score. The chart and table provide deeper insights into your resource balance.

Key Factors That Affect Colony Sustainability

• Technological Efficiency: The effectiveness of hydroponics, water recycling, and power generation directly impacts resource production. Improving this is a key goal in Terraforming Cost Analysis.
• Population Growth Rate: A rapidly growing population can strain resources if production doesn’t scale at a similar or greater rate.
• Environmental Hazards: External threats like radiation storms, micrometeoroid impacts, or atmospheric instability can lower the Environmental Stability score.
• Resource Depletion: For colonies reliant on mined resources, the rate of depletion is a critical long-term sustainability factor.
• Social Cohesion & Morale: While not a direct input, low morale can lead to lower productivity and higher consumption, indirectly affecting the score.
• Maintenance & Redundancy: The age and reliability of equipment are core to the Environmental Stability percentage. A colony with redundant life support systems is far more sustainable. Planning for this is part of building a Colony Ship Capacity Planner.

Frequently Asked Questions (FAQ)

Q: What is a “unit” of resources?
A: A “unit” is an abstract measure representing a standardized daily requirement for one person, including a balanced mix of nutrition, hydration, and breathable air. This allows the calculator to remain flexible for different colony types.

Q: Why did my score become negative?
A: A negative score occurs when your colony’s ‘Daily Net Resources’ are negative, meaning your population is consuming more than it produces each day. This is a highly unsustainable state.

Q: How important is the Environmental Stability percentage?
A: It is critically important. A colony can have a massive resource surplus, but if its life support has a high chance of failure (a low stability score), its long-term prospects are poor. It acts as a risk multiplier.

Q: What is a good Sustainability Score to aim for?
A: Any score above 10 is generally considered stable. Scores above 30 indicate a thriving, highly resilient colony capable of expansion. Scores below 0 are critical and require immediate attention.

Q: How does ‘Storage Autonomy’ work?
A: It calculates how many days your colony could survive on stored resources alone if all production suddenly stopped. It is a key measure of short-term resilience against catastrophic failures.

Q: Can this calculator be used for underwater or sealed-arcology habitats?
A: Yes. The principles are the same. The calculator is agnostic to the colony’s location, as long as it’s a closed system where production and consumption can be measured.

Q: How can I improve my score?
A: You can improve your score by increasing resource production (e.g., building more farms), decreasing consumption (e.g., rationing or more efficient recycling), or improving the reliability of your life support systems to raise the stability percentage.

Q: Does this account for trade or external supply?
A: No, this calculator is designed to measure self-sustainability. To account for trade, you would add the net daily import/export amount to the ‘Daily Resource Production’ value. For more complex logistics, see our guide on Interstellar Travel Time.

Related Tools and Internal Resources

Explore our other calculators and guides to help with your colonization planning efforts.