LEO Survivability Estimator
Verification Report
Verification Report — LEO Survivability Estimator
Status: PASS | Checks passed: 14 / 14 (100%) | Generated: 2026-06-25T16:34:31.994Z
What is verified
The estimator is a first-order atmospheric-drag orbital-decay model (near-circular orbit, drag-only secular decay, piecewise-exponential atmosphere scaled by solar activity). Verification asserts the model lands in the correct physical regime and obeys the correct monotonic relationships against well-known LEO behaviour — it is a screening tool, not a high-fidelity reentry predictor.
Reference case
3U CubeSat — mass 4 kg, drag area 0.03 m², Cd 2.2 (ballistic coefficient ≈ 60.6 kg/m²).
| Start altitude (mean solar) | Modelled lifetime |
|---|---|
| 300 km | 0.06 yr |
| 400 km | 0.51 yr |
| 500 km | 3.09 yr |
| 600 km | 15.78 yr |
Checks
| Check | Detail | Result |
|---|---|---|
| Density decreases with altitude (200>400>600 km) | rho200=2.79e-10 rho400=3.73e-12 rho600=1.45e-13 kg/m^3 | PASS |
| Density at 400 km in expected ~1e-12 kg/m^3 regime | rho400=3.73e-12 kg/m^3 | PASS |
| 3U @300 km decays fast (< 1 year, > 1 week) | 23 days | PASS |
| 3U @400 km lifetime in ~0.3–6 yr band (mean solar) | 0.51 yr | PASS |
| 3U @600 km is long-lived (> 8 yr) | 15.8 yr | PASS |
| Lifetime increases with altitude (300<400<500<600) | 0.06 < 0.51 < 3.09 < 15.78 yr | PASS |
| Doubling mass roughly doubles lifetime (1.6–2.4x) | ratio=2.00x | PASS |
| Bigger drag area shortens life | A=0.06 -> 0.26 yr < 0.51 yr | PASS |
| High solar activity shortens lifetime vs low (>2x effect) | low=6.2 yr, high=1.0 yr | PASS |
| Quadrature is step-size stable (<2% drift 0.5km vs 0.05km) | drift=0.00% | PASS |
| Min safe altitude found for 3-yr requirement | 498 km | PASS |
| Lifetime at min-safe altitude ≈ required (±5%) | life=3.00 yr vs req 3.00 yr | PASS |
| Ballistic coefficient m/(Cd*A) computed correctly | BC(3U)=60.6 kg/m^2 | PASS |
| Live tool inlines the canonical decay formula (drift guard) | formula + MU present | PASS |