What falls from the sky — nature's rain of rock, and ours of metal

Consider: the sky already rains. Thousands of tonnes of meteoric rock burn into the upper atmosphere every year and always have. The question this chart asks is when our returning satellites become a comparable rain — of aluminum instead of stone.

In plain terms: scientists' estimates of nature's yearly delivery disagree by a factor of fifty, so the honest comparison is bracket-against-bracket, shaded where they overlap. Today's whole fleet sits comfortably inside the natural range. IF every filing were granted and honored (three big IFs, below), the first milestone tier would reach the middle of the natural range — its middle estimate above nature's central value — and the US 50% tier's middle estimate would top the entire natural range, though its low end still falls inside it. No line here is a forecast, and none carries a date. Pick whose rain to watch — the buttons below work anywhere; the precise chart underneath is the record.

nature's rain of rock — central estimate15,000 t/yr

0.16×

of nature's central delivery

ours — today's fleet, everyone2,437 t/yr

The two lower rows stand on three loud IFs — IF every filing were granted, IF each honored its deployment milestone, and IF that stock flew at trigger-band-like shells on 5-year lives. Column arithmetic under the machinery's own rules — not a band forecast: filings are options, not fleets.

AS FILED · CLAIMED The official voice: filed design lives are 5, 5, and 7 years (the operators' own Schedule S filings) — the 5-year life ASSUMED in these brackets matches the filings; unit-mass classes here bracket the filings' own demise-analysis masses (2.0–2.5 t). On this chart the official numbers and ours largely agree — the three IFs, not the inputs, carry the uncertainty. Sources: the filings (primary), paper §7.4.

MODELED Fleet brackets: seeded reconstruction (seed 20260717, N=100k); unit mass ASSUMED (the dominant sensitivity), 5-year design life ASSUMED. Natural background SOURCED (Duprat et al. 2021 central; method-to-method range carried as a range, not a distribution). The rain panel's dots are ILLUSTRATIVE — fall rates proportional to the medians, visually capped at 3× nature's central with the cap disclosed on-screen; the numerals are the record. Whiskers are p05–p95 of the assumed-input sweep; the shaded band is a between-methods range — different kinds of uncertainty, drawn differently on purpose. "Middle estimate" above = the median. Source: reentry_mass_results.json; if a number here and a number in that file disagree, the file wins.

In the paper: §4.7 (what comes back down) · §6.3 (the milestone arithmetic and its IFs)