The tree · Biology · Happens to the world · Could be decided within 5 to 20 years
A shielding system flown in space cuts the deep-space radiation dose to a crew by half
Beyond Earth's magnetic field, galactic cosmic rays deliver a dose that puts a multi-year mission near or past current career limits, and the heavy nuclei in that radiation are hard to stop with thin walls. Passive routes (thick water or hydrogen-rich walls, regolith) and active routes (superconducting magnetic shields) both exist on paper. A flown demonstration that halves the dose makes rotations of months at an outer site a matter of engineering rather than of accepting the risk.
The test: what counts as it having happened
A shielding system flown beyond low Earth orbit is measured to reduce the dose equivalent from deep-space radiation (the galactic cosmic rays that Earth's magnetic field otherwise keeps out), including secondary particles, at a crew position inside an occupiable volume, by fifty percent or more compared with the interior dose of a current pressure vessel (a space-station or Orion-class hull), reported in a peer-reviewed publication.
Settled by: The peer-reviewed flight measurement; the publication's measurement protocol (matched conditions, reference geometry, uncertainty, shield mass and coverage) is what settles whether the comparison is fair
The odds, by how long I live
| baselineto 2071 ± 8 | moderateto 2080 | strongto 2095 | radicalto 2136 | openno deadline |
|---|---|---|---|---|
| 50% | 55% | 65% | 80% | 85% |
Each column is a different guess at how long I live, from current trends (baseline) to open-ended. The number is the chance this happens before that deadline, assuming everything it depends on happens first. As of September 8th, 2026.
Why these numbers: Thick water walls could do it today at a mass cost; halving the dose in a flown test within forty-five years is even odds because the passive route is expensive and the magnetic route waits on cheap superconductors.
What this one is worth
If this happened tomorrow and nothing else changed, the chance that I live and work off Earth by 2071 goes from 0.5% to 0.5% (too small to tell apart from chance). If it turned out no, the same number goes to 0.0% (−0.5 points).
| Longevity scenario | baseline2071 ± 8 | moderate2080 | strong2095 | radical2136 | openno deadline |
|---|---|---|---|---|---|
| The headline as it stands | 0.5% | 1.2% | 3.8% | 11% | 15% |
| If this settled yes now | 0.5% | 1.4% | 4.3% | 12% | 16% |
| If this settled no now | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% |
This is what the site says in advance, before the thing happens. When it does, the
ledger entry that records it quotes this figure beside what actually followed, so a
reader can see whether the prediction held. Worked out at the run
2026-10-11-scan by holding this step at each outcome in turn and
playing the whole tree out again, 20,000 times per
scenario. That is a throw of the dice, so a move smaller than about
0.10 points is inside the noise rather than
a finding.
What the ledger says about this step
- Forty-one steps had their criteria tightened so that two readers would agree when each has happened, with no number moved for that alone 2026-09-20 The tree itself changed
The last 3 checks
Once a week the tree is read against the news, node by node, against the test above. Open a line to see what that week held. Every check ever made on this node is on the Radar page.
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2026-11-01 Nothing new
No peer-reviewed flight measurement of a shielding system halving the dose was found. Artemis I data showed the storm shelter location read about half the cabin in the Van Allen belts, and Artemis II peer-reviewed dosimetry is not yet out, so neither meets the criterion (no GCR comparison to a reference hull).
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2026-10-04 Nothing new
No peer-reviewed flight measurement of a shield halving deep-space dose appeared. Artemis I and II radiation work, including the AstroRad vest, is about solar events and orientation, not a matched 50 percent GCR comparison.
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2026-09-19 Nothing new
The relevant publications found, a February 2026 shielding-experiment design paper and a modeling study claiming a 50 percent dose reduction, both predate the window and are design or ground studies, not a beyond-low-Earth-orbit flight measurement.
Revisions
| Date | Field | From | To | Why |
|---|---|---|---|---|
| 2026-09-19 | resolution | dose at the crew position compared with an undefined unshielded reference | dose equivalent, including secondary particles, at a crew position inside an occupiable volume, compared with the interior of a current pressure vessel | Step 27 outside-model review, items 5 and 51 (docs/reviews/2026-09-19-rulings.md): an ordinary hull's mass could otherwise satisfy the node, a thick shield around a dosimeter is not a crew cabin, and thin shields can raise the secondary-particle dose; the measurement protocol goes in the source note. Decided September 19th, 2026. |
Notes
The magnetic route depends on high-temperature superconductors at practical cost, an energy node; drawn at step 7.
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The record itself is data/B-biology.toml in the public repository.