diff --git a/safety/requirements/roadmap-requirements.yaml b/safety/requirements/roadmap-requirements.yaml
index 7093c558..a523bad6 100644
--- a/safety/requirements/roadmap-requirements.yaml
+++ b/safety/requirements/roadmap-requirements.yaml
@@ -543,3 +543,58 @@ artifacts:
       model: claude-opus-4-8
       timestamp: 2026-07-08T22:48:04Z
     release: v0.7.0
+
+  - id: REQ_ENGINE_COMPARISON
+    type: requirement
+    title: Benchmark and differentially validate kiln against the safety-critical Rust interpreter field (NASA spacewasm, DLR-FT), not only wasmtime
+    description: >
+      kiln's differential/perf comparisons must include its TRUE peers — the
+      safety-critical Rust WebAssembly interpreters — besides the wasmtime JIT
+      (the "unverified TCB" foil of #283). Two peers, same niche as kiln
+      (Rust, no_std-friendly, fuel-bounded, deterministic, cert-oriented):
+        - NASA spacewasm (github.com/nasa/spacewasm): flight-compliant ground-up
+          Rust interpreter for on-board spacecraft; design levied from
+          flight-software standards; deterministic dynamic-memory model,
+          streaming for low peak memory, CoreMark + libfuzzer; draws on wasmi,
+          wasm3, DLR-FT.
+        - DLR-FT/wasm-interpreter (github.com/DLR-FT/wasm-interpreter): minimal
+          in-place Rust interpreter from DLR Institute of Flight Systems for
+          avionics (ED-12C/DO-178C, ED-217/DO-332); passes the full WAST suite
+          minus unfinished proposals; fuel halt/refill/resume (mirrors kiln's
+          resumable-fuel model); live instance migration. DASC 2025 paper "On
+          the Design of a WebAssembly Interpreter for Aviation." NASA spacewasm's
+          requirements are levied from this work.
+      Two workstreams. (1) Differential correctness — extend SR-35/#401: run a
+      multi-oracle differential across {kiln, wasmtime, spacewasm, DLR-FT, AND
+      the VERIFIED reference interpreter WasmRef-Isabelle (PLDI 2023)}. The tiers
+      carry different signal: WasmRef-Isabelle is the machine-checked GOLD oracle
+      (a kiln-only disagreement with it is a kiln correctness bug, full stop);
+      the safety-critical Rust peers (spacewasm, DLR-FT) are cheap-to-embed
+      cross-checks whose agreement is high-signal and whose disagreement flags a
+      spec-interpretation delta worth a note; wasmtime is the JIT baseline. Per
+      SR-35, "an interpreter you also wrote is not its own oracle" — so the
+      verified leg is load-bearing, not optional. Cross-check the WAST suite +
+      fuzz-generated modules across all engines. (2) Competitive matrix
+      — measure kiln vs the field on WAST conformance pass rate, performance
+      (CoreMark-style + the per-poll micro methodology from REQ_ASYNC_BENCH),
+      peak/deterministic memory, no_std/no_alloc footprint, and resumable-fuel
+      determinism — AND the verification-evidence axis where kiln is meant to
+      LEAD: Verus + Lean/Aeneas proofs, witness MC/DC on the real Wasm, sigil
+      attestation, rivet end-to-end traceability (spacewasm/DLR are
+      cert-DESIGNED but not proof-carrying / MC/DC-attested to this stack level).
+      "Outcompete" = lead decisively on verification evidence while matching or
+      beating on conformance + determinism. Research / benchmark-infrastructure
+      direction, not a defect.
+    status: proposed
+    release: v0.7.0
+    tags: [benchmark, differential-testing, oracle, conformance, positioning, research, direction, release-v0.7.0]
+    links:
+      - type: derives-from
+        target: SR-35
+    fields:
+      upstream-ref: https://github.com/pulseengine/kiln/issues/413
+      note: >
+        Peer field: NASA spacewasm + DLR-FT/wasm-interpreter. Sharpens #283
+        (positioning vs the unverified Wasmtime TCB) to also cover the
+        cert-designed-but-unproven Rust field. Reuses the WAST mechanical oracle
+        (REQ_FUNC_022) and the executor-comparison bench methodology.