aster-mission-mcp

An MCP server exposing a validated asteroid-mission astrodynamics core — with evidence-carrying outputs and structured refusals. Every numeric result carries per-leaf confidence and provenance; when a request falls outside validated ground, the server refuses with the reason and what would help, instead of extrapolating.

Install / run

npx aster-mission-mcp

Node >= 18. Speaks MCP over stdio (spec 2025-11-25, SDK 1.29.0).

Tools (7)

| Tool | What it does | Structured refusals | | --- | --- | --- | | search_bodies | Search the closed-world Slice 9 NEA catalog by designation, name, orbit class, and Lambert screening status. | none | | get_body | Return one full Slice 9 catalog body record with Lambert screening status and quantity leaves. | not_found | | porkchop_scan | Run a bounded Lambert grid and return the lowest-C3 feasible cells. | not_found, out_of_envelope | | explain_cell | Return the ordered derivation trail for one departure/TOF cell. | not_found, out_of_envelope | | dla_feasibility | Return DLA and launch-site screening verdicts for one Lambert cell. | not_found, out_of_envelope | | estimate_mission_cost | Return the Slice 13 delivered-mass screening chain for one Lambert cell and vehicle. | not_found, out_of_envelope | | get_validation_report | Read the committed solver-validation artifacts without recomputing them. | none |

Resources (4)

| URI | Contents | | --- | --- | | aster://reference/launch-vehicles | Launch vehicle C3 payload curves and provenance. | | aster://reference/dla-site-bands | Launch-site DLA screening bands. | | aster://reference/catalog-schema | Slice 9 catalog and screening-cache field schema. | | aster://reference/dv-stack-model | Delta-v and delivered-mass screening model constants. |

The Honesty Model

Outputs are evidence envelopes (envelope_version 1): every Quantity leaf carries confidence and resolving source IDs; freshness is explicit via as_of; infeasibility is a value, not an error. Refusals are structured results — code, reason, what_would_help — not exceptions. Example (a real one, pinned as a committed fixture):

{
  "code": "out_of_envelope",
  "reason": "falcon-heavy-expendable publishes payload anchors only for C3 0 through 55 km^2/s^2; requested cell is C3=2928.933 km^2/s^2.",
  "what_would_help": "choose a vehicle whose curve covers C3=2928.933, or a cell with lower C3"
}

Validation

Lambert core validated against poliastro 0.17.0 as external oracle: M=0 max relative error 3.428650990914828e-14; multi-rev magnitude-only max relative error 3.5979389805439233e-12; DLA vector max angular separation 5.737702974878478e-13 degrees and max DLA delta 5.613287612504791e-13 degrees; cost oracle STRICT max/RMS 1.18%/0.55%, OBSERVED max/RMS 3.11%/2.10%. Behavioral eval: Result: 10/10 PASS across provenance, class-labeling, refusal, and boundary categories — committed at mcp/eval/.

Limits

• Catalog: 41,906 near-Earth asteroids; searches are paged, coverage fields say so.
• Ephemeris span: 2025-12-31 through 2040-12-30 — requests outside it refuse rather than extrapolate.
• Provenance hashes: live per-path git hashes in a checkout; build-baked package commit under npx (granularity loss disclosed in the envelope note).

Part of the Aster mission-planning project.