RES-02 · Landmark studies · Research

Landmark Studies & Cohorts

Multi-omics LEO short-duration LEO long-duration Terrestrial analog Public Student Clinician Researcher

draft AI-assisted Last reviewed: Pending review · Reviewer: Pending review

Bottom line

Landmark spaceflight studies are small: one twin pair, four civilians, or a few dozen ISS astronauts. Their value is depth and long follow-up, not sample size. ◆◆◆◆ High · F

Proposed certainty (◆ High → ◇ Very low) and evidence-type tags: F flight · A analog · M model/animal · C computational · E expert/operational/standards. AI-proposed, pending reviewer confirmation. How to read the grades.

STU-01 · landmark study · draft

NASA Twins Study

One identical twin spent a year on the ISS while his brother stayed on Earth as a genetic control. Most changes reversed within six months, but some did not.

◆◆◇◇ Low · F

STU-02 · landmark study · draft

Inspiration4 & SOMA

The 2024 Nature package on the first all-civilian orbital crew. It found that most changes from a 3-day flight reversed, and it launched an open atlas of astronaut biology.

◆◆◇◇ Low · F E

STU-03 · landmark study · draft

ISS long-duration cohorts

Most of what clinicians know about 6-month spaceflight comes from cohorts of 4 to 46 ISS astronauts. Key studies, what they found, and their limits.

◆◆◆◇ Moderate · F

STU-04 · landmark study · draft

Bed-rest studies

Lying in bed tilted 6° head-down for weeks reproduces many effects of weightlessness. It is the workhorse for testing countermeasures, with important blind spots.

◆◆◆◇ Moderate · A

How to use these pages

Each study page explains what was done, the key findings, what returned to normal and what didn’t, the limitations, and where to find the data. The studies are small, so focus on the direction and consistency of findings rather than exact percentages [1][2][3][4].

Evidence profile

Overall certainty: ◆◆◆◇ Moderate (proposed)
Evidence types: F · Flight dataA · Terrestrial analog
Literature through: 2026-10-14

Requirements referenced 0

No NASA-STD-3001 requirement maps directly to this page. See the standards quick reference.

References 4

Garrett-Bakelman FE, et al. The NASA Twins Study: a multidimensional analysis of a year-long human spaceflight. Science. 2019;364(6436):eaau8650. doi:10.1126/science.aau8650 PMID:30975860 Peer-reviewed F
Overbey EG, et al. The Space Omics and Medical Atlas (SOMA) and international astronaut biobank. Nature. 2024;632:1145–1154. doi:10.1038/s41586-024-07639-y PMID:38862028 Peer-reviewed F
Scott JM, et al. Effects of exercise countermeasures on multisystem function in long duration spaceflight astronauts. NPJ Microgravity. 2023;9:11. doi:10.1038/s41526-023-00256-5 PMID:36737441 Peer-reviewed F
Hargens AR, Vico L. Long-duration bed rest as an analog to microgravity. J Appl Physiol. 2016;120(8):891–903. doi:10.1152/japplphysiol.00935.2015 PMID:26893033 Peer-reviewed A

Machine-checked on 2026-10-14: each URL resolved, each DOI's title/journal/year matched via Crossref, and claims were checked against the source text (abstract or full NASA page). Human verification against full text is still required before review. NASA documents are U.S. Government works (public domain) and are summarized with attribution; journal articles are summarized, not reproduced.

Article info

Authors: Pending (AI-assisted draft)
Reviewer: Pending review
Last reviewed: Pending review
Literature through: 2026-10-14
AI-assisted: Yes (disclosed)
COI: Pending
License: CC BY-SA 4.0
Use: Educational only · Disclaimer
Cite this version: Pending first edition