Stage 5 — Design, Trade Studies & Risk
Design specs, alternatives, weighted criteria, risk register.
The Design stage produces three intertwined output types: design specifications for each component, trade studies that documented the key design decisions, and a risk register that calls out what could go wrong.
Design specifications
For each component in the decomposition, a design spec captures:
- Allocated requirements — what the component must do
- Internal design — chosen approach, key parameters, interfaces
- Resource budgets — mass, power, data, thermal allocations
- Verification activities — how each requirement will be verified (Inspection / Analysis / Demonstration / Test)
- Validation activities — how the component will be shown to meet stakeholder needs in operation
Design specs are the most prose-heavy artifacts in the bundle.
Trade studies
A trade study captures a design decision: "given these alternatives, weighed against these criteria, here is the choice and why".
Each trade study has:
- A statement of the question (e.g., "Which propulsion type for station-keeping?")
- 2–5 alternatives with descriptions
- 3–6 evaluation criteria, each with a weight (0–1, summing to 1)
- A score per (alternative, criterion) pair
- The weighted total per alternative
- The selected alternative + rationale
The pipeline generates trade studies for the design decisions it identifies as substantive — typically 2–5 trade studies per Phase-1.4 run.
Risk register
Risks are surfaced alongside the design. Each risk has:
- A statement (the bad outcome)
- A likelihood score (1–5)
- An impact score (1–5)
- A risk index (likelihood × impact)
- A mitigation strategy
- Affected components or interfaces
Risks are ranked by index; the top items in the register are what your reviewers will scrutinize.
How they interact
The three outputs of this stage are connected:
- Trade studies often surface or close out risks ("alternative A is riskier, alternative B mitigates that risk")
- Design specs reference the trade study that picked their approach
- Risks reference the components they affect
In the render, this shows up as cross-links between the design sections, trade study writeups, and risk register entries.
Failure modes
- Trade studies that aren't really trades — if all alternatives score the same, the AI fabricated the comparison. Spot-check that the criteria actually discriminate
- Risks without mitigations — every risk should have an action. Mitigation-free risks usually mean the model couldn't find one; flag them
- Design without budgets — a design spec without mass/power/data budgets is incomplete. Look for these explicitly