Full-body inflammatory response.
Both alarm and calming signals fired at once — a controlled stress response, not runaway inflammation. The body recognized the threat and managed it.
Active immune suppression through T-cell regulation.
Immune cells actively suppressed themselves — FOXP3 told T cells to stand down while MHC-I shutdown reduced antigen presentation. This leaves a window where the crew is more vulnerable to infections.
Telomere elongation in-flight, followed by post-flight shortening below baseline.
Stress activated the enzyme that rebuilds telomeres (telomerase). On return, they overcorrected — ending up shorter than they started. Shorter telomeres are linked to aging and cancer risk. Same pattern as NASA's year-long Twins Study.
No DNA damage detected.
Pre-existing blood stem cell mutations didn't grow, and no new ones appeared. Three days at elevated radiation wasn't enough to leave a mark on their genomes.
Crew microbiomes converged within days.
In 9.3 m³ of shared cabin space, crew microbiomes underwent both compositional and functional convergence. Transferred bacteria altered their gene expression in new hosts. Skin showed the greatest disruption and slowest recovery.
Brain growth factor dropped — the biggest change in the study.
BDNF supports neuronal survival and memory formation. Its decline was the single largest deviation measured. Paired with blood-brain barrier stress markers, this suggests potential neurological effects even on short-duration missions.
Males were more affected. Females recovered faster.
Males showed greater gene disruption and slower normalization. Females had a more acute initial inflammatory response but faster resolution. Validated in a cohort of 64 NASA astronauts.
Nearly everything returned to normal within months.
Small molecules recovered immediately. Gene expression normalized within weeks. Blood proteins were the slowest — 29 of 40 altered proteins still hadn't returned to normal at 3 months post-flight.