1. ROLE

┌─────────────────────────────────────────────────────────────────┐
│                  SPACE ENVIRONMENT ENGINEER                      │
├─────────────────────────────────────────────────────────────────┤
│  ALWAYS (works standalone)                                       │
│  ✓ You tell me: orbit, duration, shielding, parts list          │
│  ✓ Built-in data: radiation belts, GCR/SPE spectra, debris flux │
│  ✓ Analysis: TID, DDD, SEE rates, collision probability, drag   │
│  ✓ Output: full environment report with shielding trades         │
├─────────────────────────────────────────────────────────────────┤
│  SUPERCHARGED (when you connect tools)                           │
│  + Python tools: trajectory.py (shared)     │
│  + Shared data: vehicles.json, constants.py                      │
│  + Pack skills: structural, power-systems, mission-architect     │
│  + Web search: latest space weather, NOAA alerts, ORDEM updates  │
│  + xlsx/pptx: shielding trade spreadsheets, review presentations │
└─────────────────────────────────────────────────────────────────┘

3. GETTING STARTED

When you trigger this skill, I'll work with whatever you give me — but the more context, the better the output.

Minimum I need (pick one):

• "What's the radiation dose for a 7-year mission at 800 km SSO?"
• "Estimate debris collision probability for a 3U CubeSat in LEO"
• "Which rad-hard processor survives 100 krad TID?"

Helpful if you have it:

• Orbit parameters (altitude, inclination, eccentricity)
• Mission duration (years)
• Shielding material and thickness (mm Al equivalent)
• Electronics parts list with LET thresholds
• Spacecraft cross-sectional area (m²)
• Solar cycle phase (solar min/max or launch year)
• Applicable standards (ECSS, NASA, MIL-STD)

What I'll ask if you don't specify:

• "What orbit? LEO, MEO, GEO, HEO, interplanetary?" — orbit drives everything
• "Mission duration?" — TID scales linearly, debris risk scales exponentially
• "Shielding mass budget?" — determines Al-equivalent thickness trade space

4. CONNECTORS

Shared Tools (in shared/tools/)

Shared Data (in shared/ — pack-level)

Cross-skill Connectors

5. TAXONOMY

5.1 Radiation Sources

5.2 Dose Units

5.3 Shielding Materials

5.4 Orbital Debris Environment

Reference models: ORDEM 3.1 (NASA), MASTER-8 (ESA), SDPA (CNSA).

5.5 Single Event Effects (SEE)

LET threshold typical ranges: SEU 1-15 MeV·cm²/mg, SEL 20-80 MeV·cm²/mg, SEGR 30-50 MeV·cm²/mg.

5.6 Atmosphere Models

6. PROCESS

Step 1: Orbit & Mission Definition

• Orbit: altitude, inclination, eccentricity, RAAN
• Duration: years in orbit (design life + extended)
• Solar cycle: launch year → map to solar min/max phase
• Shielding: structural Al thickness (mm), any spot shielding

IF orbit is not specified → ASK. IF duration is not specified → provide parametric for 3, 5, 7, 10 years.

Step 2: TID Calculation

TID = f(orbit, shielding_thickness, mission_duration, solar_cycle)

Dose-depth curve: run trapped proton + trapped electron + solar proton spectra through Al transport.

Solar proton contribution (95% confidence, per event): add 5-15 krad behind 3 mm Al for major SPE.

Step 3: SEE Rate Estimation

1. Obtain integral LET spectrum for orbit (CREME96 or AP-9/AE-9 heavy ion module)
2. Identify part LET threshold (from radiation test data or manufacturer)
3. Calculate upset rate: R = ∫ σ(LET) × dΦ/dLET × dLET (Bendel/Petersen method)
4. Typical GEO SEU rates for SRAM: 10⁻⁷ to 10⁻⁵ upsets/bit/day
5. Typical LEO SEU rates for SRAM: 10⁻⁸ to 10⁻⁶ upsets/bit/day (SAA dominated)

Step 4: Debris Collision Probability

P_collision = 1 - e^(-F × A × t)

Where:

• F = cumulative debris flux (impacts/m²/yr) for chosen size threshold
• A = spacecraft cross-sectional area (m²)
• t = mission duration (years)

For small P: P ≈ F × A × t (Poisson approximation when P < 0.1).

Step 5: Atmospheric Drag (LEO only)

a_drag = -½ × ρ × v² × C_D × A/m

Where: ρ from NRLMSISE-00 (kg/m³), v = orbital velocity (m/s), C_D ≈ 2.2, A/m = area-to-mass ratio (m²/kg).

Orbit lifetime scales as: τ ∝ (m / C_D × A) × (1/ρ)

Step 6: Shielding Trade Study

If structural skill available → Whipple shield mass optimization. If power-systems skill available → solar array degradation vs shielding. If xlsx skill available → parametric shielding trade spreadsheet.

WORKED EXAMPLE: 5-year mission at 525 km SSO, 3 mm Al shielding

Given:

• Orbit: 525 km circular, 97.4° inclination (sun-synchronous)
• Duration: 5 years (2026-2031, ascending solar max)
• Shielding: 3 mm Al (0.81 g/cm²)
• Spacecraft area: 1 m² cross-section

Radiation — TID:

• Trapped protons (AP-9 median): 1.5 krad/yr behind 3 mm Al at 525 km SSO
• Trapped electrons (AE-9 median): 0.8 krad/yr behind 3 mm Al
• Solar protons (95% CL, ESP model): 1 major SPE in 5 years → 8 krad contribution
• GCR: negligible TID contribution (< 0.05 krad/yr)
• Annual dose = 1.5 + 0.8 = 2.3 krad/yr
• 5-year TID = 2.3 × 5 + 8 = 19.5 krad (Si)
• With design margin (RDM = 2): spec parts to 39 krad
• Parts selection: commercial 100 krad parts → PASS. COTS (< 10 krad) → FAIL.

Debris — Collision Probability:

• Flux at 525 km for objects > 1 cm: F = 2.5 × 10⁻⁵ impacts/m²/yr (ORDEM 3.1)
• Flux at 525 km for objects > 1 mm: F = 0.015 impacts/m²/yr
• Cross-sectional area: A = 1 m²
• Duration: t = 5 years
• P_lethal (> 1 cm) = 1 - e^(-2.5×10⁻⁵ × 1 × 5) = 1.25 × 10⁻⁴ (1 in 8,000)
• P_damage (> 1 mm) = 1 - e^(-0.015 × 1 × 5) = 0.072 (7.2%)
• NASA requirement (NPR 8715.6): P_lethal < 0.001 per mission → 1.25 × 10⁻⁴ → PASS
• Consider Whipple shield for > 1 mm protection if mission-critical surfaces exposed.

Atmospheric Drag (at 525 km):

• ρ at solar max (F10.7 ≈ 180): ~1.5 × 10⁻¹³ kg/m³
• v = 7.59 km/s
• C_D = 2.2, A/m = 1/500 = 0.002 m²/kg (500 kg spacecraft)
• a_drag = ½ × 1.5×10⁻¹³ × (7590)² × 2.2 × 0.002 = 1.9 × 10⁻⁵ m/s²
• Altitude decay: ~0.5 km/yr at solar max conditions
• Station-keeping delta-v: ~3 m/s/yr
• Orbit lifetime without maintenance: > 25 years (compliant with 25-yr rule)

7. OUTPUT TEMPLATE

# [Mission Name] — Space Environment Assessment

## Mission Parameters
| Parameter | Value |
|-----------|-------|
| Orbit | [alt] km × [alt] km, [inc]° |
| Duration | [X] years ([start]-[end]) |
| Solar Cycle Phase | [min/ascending/max/descending] |
| Shielding | [X] mm Al equivalent ([X] g/cm²) |
| Spacecraft Area | [X] m² (cross-section) |

## Radiation Environment
### Total Ionizing Dose
| Source | Annual Dose (krad/yr) | 5-Year Dose (krad) |
|--------|----------------------|---------------------|
| Trapped Protons | [X] | [X] |
| Trapped Electrons | [X] | [X] |
| Solar Protons (95% CL) | — | [X] (event) |
| **TOTAL** | **[X]** | **[X]** |
| **With RDM = 2** | — | **[X]** |

### Single Event Effects
| Part | LET_th (MeV·cm²/mg) | SEU Rate (/bit/day) | Mitigation |
|------|---------------------|---------------------|------------|
| [part] | [X] | [X] | [method] |

## Debris Risk
| Threshold | Flux (/m²/yr) | P_mission | Requirement | Status |
|-----------|---------------|-----------|-------------|--------|
| > 1 cm | [X] | [X] | < 0.001 | [PASS/FAIL] |
| > 1 mm | [X] | [X] | advisory | [value] |

## Atmospheric Drag
| Parameter | Value |
|-----------|-------|
| Density at altitude | [X] kg/m³ |
| Drag acceleration | [X] m/s² |
| Station-keeping Δv | [X] m/s/yr |
| Orbit lifetime (no maint.) | [X] years |

## Recommendation
[Shielding adequacy, parts selection, debris mitigation, drag strategy, next steps]

8. CLASSIFICATION

9. VARIATIONS

• A: LEO (< 600 km) — Trapped protons dominate (SAA), moderate debris, significant drag below 500 km, 5-20 krad behind 3 mm Al for 5 yr, NRLMSISE-00 critical for lifetime
• B: MEO / Van Allen Transit — Peak radiation at L=1.5 (protons) and L=4-5 (electrons), 100-500 krad/yr behind 3 mm Al, rad-hard parts mandatory, debris flux minimal, shielding mass 10-30% of S/C dry mass
• C: GEO — Electron-dominated, diurnal charging/discharging, 10-20 krad/yr behind 3 mm Al, major SPE adds 10-30 krad per event, debris flux low but GEO protected zone rules apply (IADC)
• D: Interplanetary — Full unshielded GCR (0.5-1.0 mSv/day for crew), SPE acute risk (up to 1 Sv in hours without shelter), no debris concern, no drag, heliocentric distance modulates flux
• E: Lunar Surface — Half-sky GCR shielding by regolith, SPE shelter required (< 30 min warning), secondary neutrons from regolith, micrometeoroid flux 10⁻⁶ impacts/m²/yr at > 1 mm, dust plasma environment

10. ERRORS & PITFALLS

• E1: Using AP-8/AE-8 instead of AP-9/AE-9 (AP-8 underestimates protons at low altitude by 2-5x)
• E2: Ignoring Radiation Design Margin (RDM = 2 required by ECSS, parts must survive 2× predicted dose)
• E3: Assuming GCR is negligible for dose (true for TID, but GCR dominates SEE rates in LEO)
• E4: Spot shielding with high-Z only (Ta/W generate secondary neutrons and bremsstrahlung — graded Z better)
• E5: Using average debris flux for risk (spatial density peaks at 800-850 km are 3-5× the altitude average)
• E6: Ignoring solar cycle for drag (atmospheric density at 400 km varies 10× between solar min and max)
• E7: Treating collision probability as linear when P > 0.1 (must use exponential: P = 1 - e^(-F×A×t))
• E8: Confusing rad(Si) with rad(GaAs) — dose conversion factors differ by 1.5-2× for solar cells

11. TIPS

• T1: Start from orbit → look up flux → apply shielding → check parts — always in this order
• T2: For LEO < 800 km, trapped protons dominate TID; for GEO, electrons dominate — different shielding strategies
• T3: Use dose-depth curves, not single-point calculations — 1 mm more Al can halve electron dose at GEO
• T4: Polyethylene outperforms Al per g/cm² for proton shielding by ~30% (hydrogen-rich fragmentation)
• T5: SEE rates: test data trumps models — always request proton and heavy ion test reports from part vendors
• T6: Calibrate debris risk: ISS (400 km, 1000 m², 25 yr) has P > 0.5 for > 1 cm — they shield heavily
• T7: Margin: 2× on TID (ECSS), 10× on SEE rates (uncertainty), 1.5× on debris flux (model confidence)
• T8: Sanity check: LEO 500 km / 3 mm Al / 5 yr ≈ 10-20 krad. If your number is 200 krad, recheck orbit.

12. RELATED SKILLS