ADR-076 — /plan ships Mars-only porkchop in v0.7; multi-destination deferred to v0.8

Status · Accepted Date · 2026-06-09 Gates · v0.7 release

Gating sentence: /plan ships a single-destination (Mars) porkchop on v0.7; the multi-destination expansion (Venus, Mercury, Jupiter/Saturn/Uranus/Neptune/Pluto flyby, Ceres/Vesta/Psyche/Bennu) lands in v0.8 per RFC-026 and issue #312.

Context

/plan advertised twelve destinations in the dropdown (mercury, venus, mars, vesta, ceres, psyche, jupiter, saturn, uranus, neptune, pluto, bennu). Only Mars rendered a real porkchop — every other destination loaded an empty grid because static/data/porkchop/ only carries a Mars Lambert-grid manifest (see ADR-026 + ADR-028 for the Lambert-grid + outer-catalogue history).

Users picking Venus or Jupiter saw a blank chart with no signal that the destination wasn't actually supported. We were promising twelve destinations and delivering one.

Decision

For v0.7 we reduce the dropdown to Mars only so the advertised surface matches what we can honestly serve. The FLYBY_ONLY and GRAVITY_ASSIST_CAVEAT_DESTINATIONS constants stay in place as dead code, so the v0.8 re-expansion is a single-line diff to the DESTINATION_IDS array.

Multi-destination support lands in v0.8 per RFC-026:

• inner-system landing porkchops for Mercury + Venus (Lambert grid, same shape as Mars)
• gas-giant + ice-giant flyby porkchops (V∞-vs-Tof, no LOI ∆v term)
• belt-target landing porkchops for Vesta, Ceres, Psyche
• single-asteroid flyby porkchop for Bennu (rendezvous shape per ADR-028)

Consequences

• Honest surface: every option in the dropdown plots a real porkchop in v0.7.
• Small UX regression: users who previously navigated to /plan?dest=jupiter now get redirected to /plan?dest=mars (existing fallback at line 220 of /plan/+page.svelte already handles unknown destinations).
• v0.8 work is well-scoped: the data layer is straightforward (one Lambert / flyby grid per destination), and the UI layer is unchanged. RFC-026 carries the implementation plan; #312 tracks delivery.

Related

• ADR-026 — original Lambert-grid Mars porkchop architecture
• ADR-028 — outer-catalogue + flyby conventions
• RFC-026 — implementation plan for v0.8 multi-destination expansion
• GH issue #312 — v0.8 delivery tracking