Trade Study Manager

• Primary: Phase A (architecture selection — this is when most trades happen)
• Supporting: Phase B (detailed subsystem trades), Phase C (change impact assessment)

Trade Study Methodology

1. Define the Trade Space

• List candidate options with a brief description of each.
• Define the "do nothing" or "baseline" option if applicable.
• Eliminate clearly infeasible options early (with documented rationale).

2. Define Evaluation Criteria (Figures of Merit)

Common criteria for space missions:

• Performance: Resolution, data rate, coverage, revisit time
• Mass: Total system mass (lighter = more launch margin or smaller LV)
• Power: Total power demand vs. available
• Cost: Development cost, operations cost, launch cost
• Risk: Technical maturity (TRL), schedule risk, supply chain
• Heritage: Flight-proven vs. novel
• Operability: Ground station needs, autonomous capability, complexity
• Lifetime: Degradation, consumables, reliability

3. Weight the Criteria

• Use pairwise comparison (AHP) or direct assignment.
• Weights must sum to 1.0 (or 100%).
• Document the rationale for weighting — this is often the most debated step.

4. Score the Options

• Score each option against each criterion (typically 1-5 or 1-10 scale).
• Scoring rules: Define what each score means before scoring (e.g., "5 = exceeds requirement with margin, 3 = meets requirement, 1 = does not meet").
• Score independently before group discussion to avoid groupthink.

5. Calculate Weighted Scores

$S_{option} = \sum_{i} w_i \times s_i$

6. Sensitivity Analysis

• Vary the weights ±20% and see if the winner changes.
• Identify which criteria are "swing factors" — small weight changes flip the result.
• If the trade is sensitive, the decision needs more analysis before commitment.

Trade Matrix Format

Common Space Mission Trades

Reference trades that come up repeatedly:

• Orbit: LEO (low latency, high drag) vs. MEO vs. GEO (large coverage, high delta-v, radiation)
• Propulsion: Chemical (simple, high thrust) vs. Electric (efficient, slow) vs. Cold gas (simple, low performance)
• Power: Solar (common, distance-limited) vs. RTG (deep space, regulatory) vs. Battery-only (short missions)
• Constellation: Single high-capability vs. distributed lower-capability (coverage vs. cost)
• Launch vehicle: Rideshare (cheap, constrained orbit) vs. Dedicated (expensive, flexible)

Output Format

1. Trade Study Report (trade_report.md): Decision question, options, criteria, weights, scoring matrix, sensitivity analysis, and recommendation with rationale.
2. Decision Record: One-paragraph summary capturing: "We chose [Option X] because [key reasons], accepting [trade-offs]."

Interface

• Reads from: /requirements/ (mission objectives and constraints), any existing /analysis/ outputs that inform the trade
• Writes to: /analysis/trade-study-manager/
• Consumed by: All downstream skills (the trade decision shapes the entire mission architecture)