src/engines/rocket.py

"""
PHI-Arc Engine PHM — Liquid Propellant Rocket Engine Model
Reference: RS-25 / RL10 class expander/bleed cycle
Certification: NASA-STD-5012, MIL-STD-1540, ECSS-E-ST-32-02
"""
import numpy as np
from typing import Dict, List
from .base_engine import BaseEngine

GAMMA = 1.25
CP = 2800.0
P_SL = 101325.0
T_ISA_SL = 288.15
LAPSE = 0.0065
LHV_LOX_LH2 = 119.90e6

class RocketEngine(BaseEngine):
    def __init__(self):
        super().__init__(
            name="RS-25 Class Rocket Engine",
            engine_type="rocket",
            ata_chapters={
                "71-00": "Powerplant",
                "73-10": "Propellant System",
                "75-40": "Nozzle",
                "77-10": "Engine Controls"
            }
        )
        self._build_fault_library()
        self.cert_standards = [
            "NASA-STD-5012 — Structural Requirements and Factors of Safety",
            "MIL-STD-1540 — Product Verification Requirements",
            "ECSS-E-ST-32-02 — Structural Factors of Safety",
            "AIAA S-081 — Liquid Rocket Engine Standards"
        ]

        self.eta_c = 0.85
        self.eta_b = 0.98
        self.eta_n = 0.97
        self.A_throat = 0.08
        self.A_exit = 4.0
        self.Of_ratio = 6.0
        self.Pc = 20.0e6
        self.EGT_REDLINE = 3500.0
        self.EGT_WARN = 3300.0

    def _build_fault_library(self):
        self.fault_library = [
            {
                "id": "F1", "name": "F1 — Injector Face Erosion / Blockage", "ata": "ATA 73-10",
                "mechanism": "Combustion instability or cavitation causes injector face erosion or blockage. Propellant distribution becomes asymmetric, combustion efficiency drops, chamber pressure oscillates.",
                "leading": "Pc oscillation↑ + η_c↓ + thrust variation↑", "color": "#e74c3c",
                "levels": [[0.99,1.00,1.00],[0.95,1.00,1.00],[0.91,1.00,1.00]],
                "actions": [
                    "Injector face inspection (AMM 73-10-00-200-801)",
                    "Injector element replacement (AMM 73-10-00-400-801)",
                    "Full injector assembly replacement (AMM 73-10-00-720-801)"
                ],
                "cert_requirements": [
                    "NASA-STD-5012 4.1 — Injector must survive declared combustion cycles",
                    "MIL-STD-1540 5.2.1 — Injector flow uniformity ≥ 95%",
                    "AIAA S-081 3.1 — Combustion stability margin ≥ 20%"
                ]
            },
            {
                "id": "F2", "name": "F2 — Chamber Wall Degradation / Burn-through", "ata": "ATA 71-00",
                "mechanism": "Regenerative cooling channel blockage or wall thinning causes hot spots. Local wall temperature exceeds material limit, potential for catastrophic burn-through.",
                "leading": "Wall temp↑↑ + cooling pressure↓ + chamber deformation", "color": "#f39c12",
                "levels": [[1.00,0.99,1.00],[1.00,0.96,1.00],[1.00,0.92,1.00]],
                "actions": [
                    "Chamber wall thickness inspection (AMM 71-00-00-200-801)",
                    "Cooling channel flow test + repair (AMM 71-00-00-400-801)",
                    "Chamber replacement (AMM 71-00-00-720-801)"
                ],
                "cert_requirements": [
                    "NASA-STD-5012 4.2 — Chamber wall life ≥ declared thermal cycles",
                    "ECSS-E-ST-32-02 5.1 — Safety factor ≥ 1.25 for pressure vessels",
                    "AIAA S-081 3.2 — Burn-through probability ≤ 1e-6 per mission"
                ]
            },
            {
                "id": "F3", "name": "F3 — Nozzle Throat Erosion", "ata": "ATA 75-40",
                "mechanism": "Ablative or regeneratively-cooled nozzle throat erodes under high heat flux. Throat area increases, chamber pressure drops, thrust decreases, Isp degrades.",
                "leading": "Pc↓ + thrust↓ + Isp↓ (throat area↑)", "color": "#9b59b6",
                "levels": [[1.00,1.00,0.99],[1.00,1.00,0.96],[1.00,1.00,0.92]],
                "actions": [
                    "Nozzle throat dimension check (AMM 75-40-00-200-801)",
                    "Nozzle throat insert replacement (AMM 75-40-00-400-801)",
                    "Full nozzle assembly replacement (AMM 75-40-00-720-801)"
                ],
                "cert_requirements": [
                    "NASA-STD-5012 4.3 — Nozzle life ≥ declared firings",
                    "MIL-STD-1540 5.3.1 — Throat area tolerance ±2%",
                    "AIAA S-081 3.3 — Nozzle efficiency ≥ 96%"
                ]
            },
            {
                "id": "F4", "name": "F4 — Turbopump Cavitation / Bearing Wear", "ata": "ATA 73-10",
                "mechanism": "LOX or LH2 turbopump cavitation causes flow rate drop and vibration. Bearing wear increases, seal leakage risk, potential for pump failure.",
                "leading": "Pump vibration↑ + flow rate↓ + NPSH↓", "color": "#3498db",
                "levels": [[1.00,1.00,1.00,0.02],[1.00,1.00,1.00,0.05],[1.00,1.00,1.00,0.08]],
                "actions": [
                    "Turbopump vibration analysis (AMM 73-10-00-200-801)",
                    "Turbopump bearing/seal replacement (AMM 73-10-00-400-801)",
                    "Turbopump assembly replacement (AMM 73-10-00-720-801)"
                ],
                "cert_requirements": [
                    "NASA-STD-5012 4.4 — Turbopump life ≥ declared cycles",
                    "MIL-STD-1540 5.4.1 — Cavitation margin ≥ 10% NPSH",
                    "AIAA S-081 3.4 — Pump efficiency ≥ 75%"
                ]
            },
            {
                "id": "F5", "name": "F5 — O/F Ratio Drift / Control Valve Fault", "ata": "ATA 77-10",
                "mechanism": "Propellant control valve malfunction causes oxidizer-to-fuel ratio drift. Mixture ratio outside design envelope causes combustion temperature excursion.",
                "leading": "O/F ratio drift + Tc excursion + exhaust color change", "color": "#1abc9c",
                "levels": [[0.99,1.00,1.00],[0.96,1.00,1.00],[0.93,1.00,1.00]],
                "actions": [
                    "Control valve functional test (AMM 77-10-00-040-801)",
                    "Control valve actuator replacement (AMM 77-10-00-400-801)",
                    "Full propellant control system overhaul (AMM 77-10-00-720-801)"
                ],
                "cert_requirements": [
                    "NASA-STD-5012 4.5 — O/F control accuracy ±2%",
                    "MIL-STD-1540 5.5.1 — Valve response time ≤ 50ms",
                    "AIAA S-081 3.5 — Mixture ratio stability margin ≥ 10%"
                ]
            }
        ]

    def compute_healthy_baseline(self, flight_conditions: Dict) -> Dict[str, float]:
        Pc = flight_conditions.get("chamber_pressure_mpa", 20.0) * 1e6
        Of = flight_conditions.get("of_ratio", 6.0)

        # Rocket chamber conditions
        Tc = 3500.0
        mdot_ox = Pc * self.A_throat / (3000 * Of / (Of + 1))
        mdot_fuel = mdot_ox / Of
        mdot_total = mdot_ox + mdot_fuel

        # Nozzle expansion
        Pe = P_SL
        Ve = (2 * CP * Tc * (1 - (Pe/Pc)**0.2))**0.5
        thrust = mdot_total * Ve + (Pe - P_SL) * self.A_exit
        Isp = thrust / (mdot_total * 9.81)

        return {
            "EGT": Tc - 273.15, "thrust": thrust/1000, "Isp": Isp,
            "Pc": Pc/1e6, "mdot": mdot_total, "Of": Of
        }

    def compute_fault_signatures(self, baseline: Dict, flight_conditions: Dict) -> List[List[Dict]]:
        results = []
        for f in self.fault_library:
            lvl_vals = []
            for lv in range(3):
                m = f["levels"][lv]
                Pc = flight_conditions.get("chamber_pressure_mpa", 20.0) * 1e6 * m[0]
                Of = flight_conditions.get("of_ratio", 6.0)
                eta_c = self.eta_c * m[1]
                eta_n = self.eta_n * m[2]
                mech_loss = m[3] if len(m) > 3 else 0

                Tc = 3500.0 * eta_c
                mdot_ox = Pc * self.A_throat / (3000 * Of / (Of + 1)) * (1 - mech_loss)
                mdot_fuel = mdot_ox / Of
                mdot_total = mdot_ox + mdot_fuel

                Pe = P_SL
                Ve = (2 * CP * Tc * (1 - (Pe/Pc)**0.2))**0.5 * eta_n
                thrust = mdot_total * Ve + (Pe - P_SL) * self.A_exit
                Isp = thrust / (mdot_total * 9.81) if mdot_total > 0 else 0

                lvl_vals.append({
                    "EGT": Tc - 273.15, "thrust": thrust/1000, "Isp": Isp,
                    "Pc": Pc/1e6, "mdot": mdot_total, "Of": Of
                })
            results.append(lvl_vals)
        return results

    def classify_fault(self, measured: Dict, baseline: Dict, fault_sigs: List[List[Dict]]) -> Dict:
        params = ["EGT", "thrust", "Isp", "Pc"]
        user_sig = np.zeros(4)
        for i, p in enumerate(params):
            if p in measured and p in baseline:
                denom = baseline[p] * 0.10 if p in ["thrust", "Isp", "Pc"] else (self.EGT_REDLINE - baseline[p])
                user_sig[i] = (measured[p] - baseline[p]) / denom if denom != 0 else 0

        scores = []
        for fi, f in enumerate(self.fault_library):
            best_score = -1e9
            best_lvl = 0
            for lv in range(3):
                fv = fault_sigs[fi][lv]
                sig = np.zeros(4)
                for i, p in enumerate(params):
                    denom = baseline[p] * 0.10 if p in ["thrust", "Isp", "Pc"] else (self.EGT_REDLINE - baseline[p])
                    sig[i] = (fv[p] - baseline[p]) / denom if denom != 0 else 0
                denom = (np.linalg.norm(sig) * np.linalg.norm(user_sig)) + 1e-9
                score = np.dot(sig, user_sig) / denom
                if score > best_score:
                    best_score = score
                    best_lvl = lv
            sev = max(0.0, min(1.0, best_score))
            scores.append({"fi": fi, "f": f, "sev": sev, "lvl": best_lvl, "sig": user_sig})

        scores.sort(key=lambda x: x["sev"], reverse=True)
        magnitude = np.linalg.norm(user_sig)
        status = "HEALTHY" if magnitude < 0.12 else ("INDETERMINATE" if scores[0]["sev"] < 0.30 else "FAULT_DETECTED")

        return {
            "base": baseline, "faults": fault_sigs, "scores": scores,
            "user_sig": user_sig, "status": status,
            "thresholds": {
                "EGT_warn": self.EGT_WARN, "EGT_maint": self.EGT_REDLINE,
                "Pc_warn": baseline["Pc"] * 0.95, "Pc_maint": baseline["Pc"] * 0.90
            },
            "deviations": {p: user_sig[i] for i, p in enumerate(params)}
        }

    def get_parameter_labels(self) -> List[str]:
        return ["EGT", "Thrust", "Isp", "Chamber Pressure"]

    def get_parameter_units(self) -> Dict[str, str]:
        return {"EGT": "°C", "thrust": "kN", "Isp": "s", "Pc": "MPa"}

    def get_input_fields(self) -> List[Dict]:
        return [
            {"name": "chamber_pressure", "label": "Chamber Pressure", "default": 20.0, "unit": "MPa", "type": "number"},
            {"name": "of_ratio", "label": "O/F Ratio", "default": 6.0, "unit": "", "type": "number"},
            {"name": "EGT", "label": "Combustor Temp", "default": 3200.0, "unit": "°C", "type": "number"},
            {"name": "thrust", "label": "Thrust", "default": 2000.0, "unit": "kN", "type": "number"},
            {"name": "Isp", "label": "Specific Impulse", "default": 450.0, "unit": "s", "type": "number"},
            {"name": "Pc", "label": "Chamber Pressure (measured)", "default": 20.0, "unit": "MPa", "type": "number"}
        ]