Mock M1 · Choosing a Future Lunar Base Location
Multi-criteria AHP / TOPSIS Decision-makingThe problem
The International Lunar Coordination Office (ILCO) is selecting the site of humanity's first permanent crewed lunar base, to be operational by 2035. The decision must balance scientific value, engineering feasibility, resource availability, and political accessibility. Your team has been hired to build a defensible quantitative model.
Background
Candidate landing zones cluster around four broad regions on the Moon:
- Mare Tranquillitatis — equatorial, near-side, flat, well-mapped (Apollo 11).
- Shackleton Crater rim (South Pole) — permanent shadow inside (likely water ice), near-permanent sunlight on the rim.
- Aristarchus Plateau — geologically diverse, volcanic features, mid-latitude.
- Mare Orientale (Far side) — radio-quiet, scientifically pristine, but no direct Earth line-of-sight.
Requirements
- Identify the key factors a base-selection model must consider. Justify each. Distinguish "must-haves" (hard constraints) from "nice-to-haves" (soft criteria).
- Build a quantitative model that scores candidate sites against your criteria. Choose your weighting scheme and explain why.
- Apply your model to the four candidate regions above. Produce a final ranking with scores.
- Extend the model to handle:
- Two-base architectures (one near-side, one far-side) — does any candidate combination dominate?
- Uncertainty in resource estimates (ice quantity, regolith composition).
- Sensitivity analysis: identify the criteria whose weights most affect the ranking.
- Write a 1–2 page memo to the ILCO Director recommending a site and explaining the trade-offs in plain English.
Useful information
- Solar illumination at the lunar south pole: ~80–90% annual (rim peaks) vs. ~50% at the equator (14-day day/night cycle).
- Estimated water ice in Shackleton crater: 100 million to several billion kg (high uncertainty).
- Lunar surface temperature swing: −173 °C (night) to +127 °C (day) equatorial; near-poles much milder.
- Time from Earth launch to the Moon: ~3 days; communication delay: ~1.3 s round trip (line-of-sight only).
- Radiation environment: galactic cosmic rays ~30 rem/yr surface dose; solar particle events spike to lethal levels.
Solution sketch
Factors
| Category | Specific factor | How to measure |
|---|---|---|
| Power | Annual solar illumination % | Lunar Reconnaissance Orbiter data |
| Resources | Estimated water ice (kg accessible) | Reports / LCROSS data |
| Resources | Regolith metal/oxygen fraction | Sample-return chemistry |
| Engineering | Surface slope (°) | LRO LOLA altimetry |
| Engineering | Thermal cycling severity | Day-night ΔT |
| Communications | Earth line-of-sight % time | Geometric calculation |
| Safety | Radiation shielding (natural) | Lava tube proximity, crater wall coverage |
| Science value | Geological diversity, never-sampled lithologies | Geologist scoring |
| Politics | Outer Space Treaty status, prior claims | Diplomatic review |
Model
Two-tier scoring:
- Hard constraints as binary filters: e.g., surface slope ≤ 10°, solar illumination ≥ 30%, line-of-sight ≥ 50% OR willingness to deploy relay satellites. Sites failing any constraint are eliminated.
- Soft criteria via TOPSIS. Weights from AHP (judgment of mission goals) averaged with EWM (data spread).
Likely result (illustrative)
Shackleton wins on resources + power but loses on direct comms and is engineering-hard (cold, dark crater interior). Mare Tranquillitatis is easy and well-mapped but resource-poor. Aristarchus has the best science value. Mare Orientale is dominated unless the model heavily weighs radio-quiet science.
The two-base extension makes Shackleton + Mare Orientale the dominant pair: Shackleton supplies water and ISRU oxygen, Mare Orientale hosts a relay-assisted far-side radio telescope. This is a real architectural debate — your model should surface it.
Sensitivity
Sample weights from a Dirichlet distribution centered on AHP outputs. Re-run TOPSIS 10,000 times. Report the probability each site wins. Shackleton typically wins ~70% of weight realizations; the other 30% are split among Aristarchus and Tranquillitatis. Mare Orientale almost never wins alone, but is robustly the second-base choice.
What we'd be grading on
- Did you separate hard constraints from soft scoring?
- Are your weights principled (AHP / EWM / hybrid), not just "we picked these numbers"?
- Did you actually engage with all four candidate regions?
- Does your sensitivity analysis produce probabilities of each ranking, not a single rerun?
- Is the memo to the ILCO Director persuasive without being technical?