ISRU Assessment Skill (In-Situ Resource Utilization)

• Primary: Phase A (ISRU vs. Earth-supply trade), Phase B (process selection and plant sizing)
• Supporting: Phase C (detailed process engineering), Phase D (in-situ demonstration planning)

Resource Availability by Body

Moon

Mars

Asteroids

• C-type: 10-20% water, organics, clays
• S-type: Metals (Fe, Ni), silicates
• M-type: High metal content (Fe, Ni, possibly PGMs)
• Extraction in microgravity is a largely unsolved engineering problem.

Analysis Workflows

1. ISRU vs. Earth Supply Trade

The fundamental trade:

• Launched cost: $C_{launch} = m_{product} \times $/kg_{to_destination}$
  • Earth to Moon surface: ~$100k-500k/kg (current), ~$10k-50k/kg (target, Starship-class)
  • Earth to Mars surface: ~$500k-2M/kg (current estimates)
• ISRU cost: $C_{ISRU} = C_{plant} + C_{power} + C_{ops}$ amortized over production lifetime.
• Break-even: ISRU wins when $C_{ISRU}/m_{produced} < C_{launch}$ over mission lifetime.

2. Process Sizing

For each ISRU process:

• Feedstock rate: Mass of raw material per mass of product (stoichiometric + losses).
• Energy requirement: $E_{spec}$ (kWh/kg product) — this is usually the dominant constraint.
  • Lunar O₂ from ilmenite reduction: ~4-8 kWh/kg O₂
  • Mars MOXIE-class electrolysis: ~5-10 kWh/kg O₂
  • Water electrolysis: ~5 kWh/kg O₂ (plus ~0.6 kWh/kg H₂ co-product)
  • Sabatier: ~2 kWh/kg CH₄ (exothermic, but needs thermal management)
• Plant mass: Typically 50-200 kg per kg/day production rate (highly dependent on TRL).
• Ancillary systems: Excavation/collection, beneficiation, storage, distribution.

3. Power Requirements

ISRU is energy-intensive. Size the dedicated power supply:

• Solar: Available on lunar dayside (~1361 W/m²) and Mars (~589 W/m²). Not available during lunar night (14 days).
• Nuclear (Kilopower/fission): 1-10 kW per unit. Enables continuous operation, night-time processing, and PSR operations. Strongly recommended for any large-scale ISRU.
• Interface with power-assessment: ISRU power is additive to spacecraft/habitat loads — flag total demand.

4. Storage & Distribution

• Cryogenic storage: LOX, LH₂, LCH₄ — boil-off management is critical.
  • Zero Boil-Off (ZBO): Active cryo-coolers, ~15-20 W/kg stored per day.
  • Passive: MLI + low-conductivity supports. Boil-off rate 0.1-1%/day depending on scale and insulation.
• Gas storage: High-pressure composite tanks for O₂, N₂ breathing atmosphere.
• Propellant transfer: Pumped or pressure-fed transfer to vehicles. Interface definition needed.

Output Format

1. ISRU Feasibility Report (isru_report.md): Available resources, process selection, plant sizing, energy requirements, and break-even analysis.
2. Production Budget: Mass/energy/time per unit product.
3. Infrastructure Requirements: Power plant, excavation equipment, storage, and distribution.
4. 🟢 / 🟡 / 🔴 status: Feasibility and TRL assessment per process.

Interface

• Reads from: /requirements/, /analysis/mission-analysis-specialist/ (destination, surface conditions), /analysis/power-assessment/ (available power for ISRU), /analysis/propulsion-assessment/ (propellant demand)
• Writes to: /analysis/isru-assessment/
• Consumed by: propulsion-assessment (in-situ propellant availability), eclss-assessment (in-situ O₂/H₂O), cost-modeling (ISRU economics vs. launch), systems-engineering-assessment (infrastructure mass/power)