Tardigrades survived the open vacuum of space for ten days in 2007, and most returned alive and reproduced
In 2007, dried tardigrades exposed to the open vacuum of space and cosmic radiation for ten days on ESA's FOTON-M3 mission mostly survived; survivors returned to Earth and laid viable eggs.
Sources
A. In September 2007, the ESA sent ~3,000 tardigrades into open space on the FOTON-M3 mission (TARDIS experiment) for ten days.
Jönsson KI et al. (2008), "Tardigrades survive exposure to space in low Earth orbit," *Current Biology* 18(17): R729–R731. (cell.com/current-biology/fulltext/S0960-9822(08)00805-1, fetched 2026-07-27) — peer-reviewed primary source; species: *Richtersius coronifer* and *Milnesium tardigradum*; experiment duration and conditions confirmed.
ESA article "Tiny animals survive exposure to space" (esa.int/Science_Exploration/Human_and_Robotic_Exploration/Research/Tiny_animals_survive_exposure_to_space, fetched 2026-07-27) — "approximately 3,000 water bears were sent into space aboard Foton-M3 for 12 days in September 2007." Independent institutional source corroborating mission and scale.
B. Most tardigrades survived the combination of space vacuum and cosmic radiation.
Jönsson et al. 2008 (*Current Biology*) — "tardigrades can survive exposure to the space vacuum." Vacuum + cosmic radiation group had high survival rates.
EarthSky reporting on the Jönsson 2008 study (earthsky.org/space/water-bears-tardigrades-into-space-iss-experiment/, fetched 2026-07-27) — "3,000 living tardigrades were ferried on a European mission to low Earth orbit and exposed to the hard vacuum of space for 10 days, with 68 percent of them surviving."
C. Survivors reproduced normally on return — viable offspring confirmed.
ScienceDaily release on the Jönsson 2008 study (sciencedaily.com/releases/2008/09/080908135906.htm, fetched 2026-07-27) — "the survivors could reproduce fine after their space trip."
EarthSky (earthsky.org, fetched 2026-07-27) — "gave birth to normal offspring." Independent corroboration.
D. Tardigrades enter a cryptobiotic "tun" state when desiccated, dropping metabolism to near zero.
PMC review, "Tardigrades in Space Research — Past and Future" (pmc.ncbi.nlm.nih.gov/articles/PMC5705745/, fetched 2026-07-27) — "In the anhydrobiotic state, the metabolic activity of tardigrades drops to a very low level." Tun formation reduces evaporative water loss by ~50%.
PMC, "New insights into osmobiosis and chemobiosis in tardigrades" (pmc.ncbi.nlm.nih.gov/articles/PMC10620314/) — cryptobiosis and tun state mechanism confirmed across multiple species; tardigrades retract limbs and contract into a barrel shape.
E. Tardigrades are found on every continent and in virtually every habitat.
PMC review on tardigrades in space research (pmc.ncbi.nlm.nih.gov/articles/PMC5705745/) — found on all seven continents, in marine, freshwater, and terrestrial habitats.
Wikipedia "Tardigrade" citing multiple primary sources — "found in nearly all environments on Earth, from mountaintops to the deep sea and from tropical rainforests to the Antarctic."
What we refused to claim
UV radiation survival. Some tardigrades survived moderate UV-A doses; those exposed to UV-B or full-spectrum UV had very low or zero survival (10–15% and 0%, per Jönsson 2008). The script does NOT claim UV survival — only vacuum + cosmic radiation.
Exact mechanism of radiation tolerance. Dsup protein and other DNA-protection mechanisms are under active research. The script claims only "survived" — no mechanism for radiation survival asserted.
Duration discrepancy: 10 vs. 12 days. Jönsson 2008 (primary) uses ~10 days; the ESA article says 12 days (possibly counting transport/recovery phases). Script uses "ten days" following the peer-reviewed paper.
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