Cost Modeling Skill

Read CONVENTIONS.md at the repo root before proceeding.

This skill produces parametric cost estimates for spacecraft, launch, and operations. It provides the cost dimension that trade-study-manager and systems-engineering-assessment need to make informed architecture decisions.

Before You Begin

Ask the user (if not already known):

1. What program type? (Government / commercial / university — cost drivers differ dramatically)
2. What cost model framework? (NASA PCEC, Aerospace USCM/SSCM, analogy-based, vendor quote, or expert judgment)
3. What is the cost reference year? (All estimates in constant-year dollars — state the base year)
4. Is this a single unit or a production run? (Learning curve applies to multi-unit buys)
5. What design phase? (Phase A estimates carry ±50-100% uncertainty; Phase C: ±15-25%)

Applicable Phases

• Primary: Phase A (ROM for proposal and feasibility), Phase B (refined estimate for confirmation)
• Supporting: Phase C (cost tracking against baseline), Phase D (actual vs. estimate comparison)

Ownership Boundary

Responsibility	Owner
Parametric cost estimates, cost risk, cost-driven trades	This skill
Mass, power, and performance budgets (cost model inputs)	Domain assessment skills
Trade study integration (cost as a criterion)	trade-study-manager

Cost Estimation Methods

1. Parametric (CER-based)

Cost Estimating Relationships express cost as a function of technical parameters:

• General form: $Cost = a \cdot X^b$ where $X$ is a driver (mass, power, data rate, etc.)
• Common CER sources:
  • USCM (Unmanned Spacecraft Cost Model): Subsystem-level CERs for unmanned missions
  • SSCM (Small Satellite Cost Model): Tuned for <500 kg spacecraft
  • PCEC (Project Cost Estimating Capability): NASA's integrated cost tool
  • NICM (NASA Instrument Cost Model): For science instruments/payloads
• Typical cost drivers by subsystem:
  • Structure: dry mass (kg)
  • Thermal: radiator area (m²), heater power (W)
  • Propulsion: propellant mass (kg), Isp class
  • EPS: solar array area (m²), battery capacity (Wh)
  • C&DH/FSW: SLOC (lines of code), processor class
  • Communications: data rate (Mbps), antenna diameter (m)

2. Analogy-Based

• Select a reference mission with known cost and similar scope.
• Adjust for differences in complexity, mass, heritage, and technology maturity.
• Best used when CER databases are unavailable or the mission is highly novel.

3. Multi-Unit Production

• Learning curve: $C_n = C_1 \cdot n^{\log_2(s)}$ where $s$ is the learning rate (typically 85-95% for spacecraft).
• Non-recurring vs. recurring: NRE (design, tooling, qualification) amortized over production quantity.
• Constellation economics: Per-unit cost drops significantly at quantities >10.

Cost Categories (WBS-Aligned)

Category	Includes
Phase A-D (Development)	Design, fabrication, AI&T, project management, systems engineering, mission assurance
Launch	Launch vehicle, launch services, range costs, insurance
Operations	Ground segment, mission operations, data processing, disposal
Reserves	Unallocated Future Expenses (UFE) — typically 25-30% of development cost

Cost Risk & Uncertainty

• Phase A: ±50-100% (order of magnitude). State as a range, not a point estimate.
• Phase B: ±25-50%.
• Phase C/D: ±15-25%.
• S-curve / Monte Carlo: If probabilistic analysis is needed, recommend tools (e.g., @RISK, Crystal Ball) rather than attempting it with napkin math.
• Cost growth: Historical average is 20-50% above initial estimate for government programs. Flag this.

Launch Cost Reference

Vehicle	LEO Capacity (kg)	Approx. Cost ($M)	$/kg LEO
Electron	300	7.5	25,000
Falcon 9 (expendable)	22,800	67	2,900
Falcon 9 (reusable)	15,600	50	3,200
Starship (target)	150,000	10-30	67-200
Vulcan Centaur	27,200	110	4,000
Ariane 6 (A62)	10,350	77	7,400

Note: Rideshare can reduce launch cost to $5k-15k/kg for small satellites.

Output Format

1. Cost Estimate Report (cost_estimate.md): WBS-level cost breakdown, methodology, assumptions, reference year, and uncertainty range.
2. Cost Summary Table: One-line-per-subsystem with NRE + recurring + total.
3. Lifecycle Cost Profile: Year-by-year spending curve if operations phase is significant.
4. 🟢 / 🟡 / 🔴 status: Cost feasibility vs. stated budget constraints.

Interface

• Reads from: /requirements/, /analysis/systems-engineering-assessment/ (mass/power budgets), /analysis/propulsion-assessment/ (propellant mass), all subsystem outputs for CER inputs
• Writes to: /analysis/cost-modeling/
• Consumed by: trade-study-manager (cost as FoM), systems-engineering-assessment (cost summary)