Partitioning the Spaceflight "Aging" Signature: What Artificial Gravity Can and Cannot Rescue
1 The Bear Creek School, Redmond, WA, USA.
* Corresponding Author
Research Article
Open Access Research Journal of Science and Technology, 2026, 18(01), 172–185.
Article DOI: 10.53022/oarjst.2026.18.1.0096
Publication history:
Received on 30 August 2026; revised on 15 October 2026; accepted on 17 October 2026
Abstract:
Astronauts return from long spaceflights with changes that resemble accelerated aging, but spaceflight combines several stressors - microgravity, radiation, launch, and confinement - so it is normally impossible to say how much of the aging-like signature is caused by the lack of gravity as opposed to the other stressors. This distinction matters because a gravity problem can be engineered away by spinning a spacecraft, while a radiation problem requires shielding or drugs. I used a unique experimental design that separates gravity from everything else: NASA/JAXA on-orbit centrifuge missions in which mice were flown at microgravity (0 g) and artificial 1 g at the same time, sharing identical radiation, launch, and confinement. Re-analyzing public RNA-sequencing data (NASA OSDR), I partitioned the mouse retinal spaceflight signature into a gravity-dependent and a gravity-independent part and estimated the fraction that artificial gravity "rescues." A naive estimate suggested gravity reverses about 75% of the signature, but a permutation test showed that roughly two-thirds of this was an artifact of selecting genes on noisy data; a bias-free estimator placed the true rescue fraction near 57%, though with wide uncertainty owing to small sample sizes. The effect pointed in the same direction across three tissues (retina 57%, thymus 40%, liver 20%). A dose-response analysis indicated that partial gravity provides little benefit - the signal only declines near full 1 g. A validated senescence gene set showed no detectable senescence induction, indicating the signature is not classic cellular aging. Finally, pathway enrichment revealed that the genes rescued by gravity are dominated by the heat-shock and unfolded protein response, identifying the gravity-dependent portion as a protein-folding stress program. These results provide the first quantitative, uncertainty-aware estimate of how much of the spaceflight signature artificial gravity can reverse, and suggest that near-full gravity would be required to capture the benefit.
Keywords:
Microgravity; Spaceflight; Aging
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Copyright © 2026 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0