Materials decisions that hold up in a design review
Strength-to-weight is the easy answer. The defensible answer accounts for allowables, lead time, and export posture — and gets written down before the CDR.
A material trade study that only compares strength-to-weight is a slide, not a decision. Real aerospace materials decisions are made across a wider set of axes, and the ones that survive a design review are the ones with the trade documented before the review — not after a reviewer asks.
The axes that actually matter
Beyond mechanical performance: environmental resistance in the actual mission profile, allowables maturity for the specific form and lot, manufacturability at the target rate, supply-chain depth (single source is a program risk regardless of the datasheet), export-control posture, and cost at both prototype and production volume. Rank by what the program will be judged on — not by what's easiest to score.
Coupons before conviction
Where the allowables base is thin, plan the coupon work early. A modest coupon campaign in month two beats a program-level surprise in month twelve, and it gives the structural analysis a defensible number instead of a knockdown assumption.
Write it down while it's fresh
The trade study document is the artifact that survives staff turnover, program re-baselines, and eventual customer audits. Written at decision time, it's a two-page memo; written months later from memory, it's incomplete.