Orbital Lifecycle Envelope (MTBOF)
Methodology
Static decay predictors are incomplete. The atmosphere varies 3× across the solar cycle; your asset lives through both ends. Reserves priced against any single percentile leave the other two unpriced. The methodology delivers all three. The M2 historical-prediction gauntlet detected the static-Fbaseline cycle-invariance limit empirically — disclosed below, not hidden.
Definitions: Fbaseline(h) is the SWADI substrate-weighted atmospheric density per altitude shell (decision #25); βrel(h) is the per-shell storm-response coefficient (decision #28); F10.7(t) and ap(t) are read at every integration step from the F2-validated GFZ-Potsdam 95-year archive (1932–2026, SHA-pinned). Three archetype windows are replayed forward from the asset's decommissioning epoch: P10 = 2008–2010 cold-sun deep solar minimum; P50 = 1976–2026 50-year nominal; P90 = 1979–1981 Cycle 21 hot-sun peak. Integrator is clamped to a 1-day max timestep so it never steps over a storm.
What you receive
- P10/P50/P90 envelope for any orbit you specify (initial altitude + A/m + decommissioning epoch).
- Solar-window-timed deorbit advisory (decision #22): "decommission today vs. maintain altitude until next solar maximum" — propellant cost vs. compliance horizon, surfaced numerically.
- Calibration receipts: M2 historical-prediction errors per asset class + envelope-containment results against documented reentries.
Deliverable: an audit JSON pinned to the snapshot SHA, plus a rendered PDF. Same form as the public artifacts in the audit charter.
Selected data points — canonical orbits
| Orbit | P10 (yr) | P50 (yr) | P90 (yr) | P10/P90 ratio | FCC 25-yr? |
|---|---|---|---|---|---|
| ISS-class 410 km A/m=0.006 | 1.98 | 1.42 | 0.72 | 2.75× | yes |
| Low-LEO 450 km A/m=0.012 | 2.05 | 1.45 | 0.76 | 2.71× | yes |
| Mid-LEO 600 km A/m=0.010 | 29.62 | 13.44 | 9.80 | 3.02× | yes |
| High-LEO 800 km A/m=0.007 | >100 | >100 | >100 | 1.00× | no |
Envelope-containment vs. documented reentries
The envelope is a forward-prediction tool. As a sanity check we replay each canonical historical reentry against its own decommissioning-epoch orbit parameters and ask: does the actual lifetime fall inside the methodology's [P90, P10] envelope? Honest result: the static-Fbaseline cycle-invariance limit now shows in the point predictions, not the envelope (M2: Skylab −54.2%, UARS +56.5%, ROSAT −30.1%).
| Asset | alt (km) | A/m | observed | P90 | P50 | P10 | result |
|---|---|---|---|---|---|---|---|
| Skylab | 433 | 0.0024 | 5.42 yr | 2.61 | 4.08 | 7.51 | inside envelope |
| UARS | 575 | 0.0120 | 5.78 yr | 5.57 | 12.17 | 16.66 | inside envelope |
| ROSAT | 565 | 0.0070 | 12.69 yr | 8.01 | 13.96 | 24.37 | inside envelope |
Replay starts from each asset's epoch_eom_iso (Skylab 1974, ROSAT 1999, UARS 2005) and integrates forward against the three archetype windows. All three documented reentries land inside the envelope (one of three in v0.4.1): the historical cohort now carries Skylab A/m 0.0024 (was 0.0036) and UARS A/m 0.0120 (was 0.0086) m²/kg, a change made in the code after v0.4.1 was published. Decision #29 articulates the v0.4.0.7 cycle-stratified Fbaseline fix; until then the limit is disclosed empirically.
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