Sensorimotor & balance

Also: Sensorimotor risk

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

Bottom line

After about 6 months in flight, walking and obstacle performance are clearly impaired and recover over about 2 weeks. ◆◆◆◇ Moderate · F
For lunar landings, NASA rates the risk 3×5 because a sensorimotor error could cause serious harm. It requires mitigation. ◆◆◆◆ High · E

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.

NASA risk title (verbatim)

Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks, Human Health, and Long-Term Health

NASA short title: Sensorimotor · HRP element: Human Health Countermeasures (HHC) · Status: Active [current research ongoing] [1]

What it is

Long flights change how the brain combines signals from the inner ear, eyes and body. This shows up as motion sickness and as problems with spatial orientation, balance, walking and fine motor control [1]. The risk peaks during and soon after gravity changes, such as manual landings, getting out of the vehicle, and early spacewalks [1].

Current evidence

After an average of 185 days on the ISS, 18 crew members took a median 48% longer to complete an obstacle course. They were estimated to recover to 95% of preflight performance in about 15 days [4].
Balance testing in 37 ISS crew members showed that head-tilt conditions revealed falls and slower recovery that a standard Romberg test missed [5].
Even a 3-day flight (Inspiration4) produced measurable eye-alignment changes, a marker of inner-ear and balance effects [6].
Open questions include manual control around gravity transitions, motion sickness after water landings, doing spacewalks soon after landing, and the effects of partial gravity [1].

NASA’s risk posture

NASA scores each risk for each design reference mission (DRM) as likelihood × consequence (LxC). Both run from 1 (lowest) to 5 (highest) on the HSRB’s 5×5 matrix [1][3]. Each score comes with a disposition, such as “Accepted”, “Requires Characterization” or “Requires Mitigation”. These ratings were last approved by NASA’s Human System Risk Board (HSRB) in 11/2024 [1].

Mission	Duration	In-mission (operations)	Long-term health
LEO	Short (under 30 d)	1x2 · Accepted	1x2 · Requires Characterization
LEO	Long (30 d–1 yr)	1x2 · Accepted	2x2 · Requires Characterization
Lunar orbit	Short	1x2 · Accepted with Monitoring	1x2 · Requires Characterization
Lunar orbit	Long	1x2 · Accepted with Monitoring	2x2 · Requires Characterization
Lunar orbit + surface	Short	3x5 · Requires Mitigation/Standard Refinement	1x2 · Requires Characterization
Lunar orbit + surface	Long	3x5 · Requires Mitigation/Standard Refinement	2x2 · Requires Characterization
Mars preparatory	Under 1 yr	1x2 · Accepted with Monitoring	1x2 · Requires Characterization
Mars planetary	730–1,224 d	4x5 · Requires Mitigation/Standard Refinement	2x2 · Requires Characterization

Copied from the Human Research Roadmap on 2026-10-14. Ratings change. Check the live record before citing.

Open knowledge gaps

NASA lists 9 knowledge gaps for this risk, 9 of them open as of 2026-10-14 [1]. Each gap ID links to its page on the Human Research Roadmap (HRR).

Show NASA’s gap list (verbatim)

Gap	NASA gap statement	Status
SM-101	Characterize the effects of short and long-duration weightlessness, with and without deep-space radiation, on postural control and locomotion (gross motor control) after G transitions.	Open
SM-102	Characterize the effects of short and long-duration weightlessness, with and without deep-space radiation, on manual control (fine motor control) after G transitions.	Open
SM-103	Characterize the effects of short and long-duration weightlessness, with and without deep-space radiation, on spatial orientation and motion sickness after G transitions.	Open
SM-104	Evaluate how weightlessness-induced changes in sensorimotor/vestibular function relate to and/or interact with changes in other brain functions (sleep, cognition, attention).	Open
SM-201	Develop and test postural control and locomotion countermeasures, including human factors aids.	Open
SM-202	Develop and test manual control countermeasures, such as vibrotactile assistance vest, and other human factors aids.	Open
SM-203	Develop and test SMS countermeasures.	Open
SM-204	Develop and test post-planetary-landing self-administered testing and rehab tool.	Open
SM-301	Test the finalized combined CM Suite in flight.	Open

Active countermeasure research

Countermeasures in development. These include preflight and in-flight sensorimotor training, self-administered rehabilitation, sensory augmentation, in-flight balance training, and new anti-motion-sickness drug formulations combined with non-drug measures [1].
Landing readiness. NASA is studying post-flight piloting on a lunar-landing motion simulator and just-in-time training [1].
Artificial gravity. NASA notes that artificial gravity from a centrifuge would prevent most of these changes [1].

Project-level detail, including status, investigators and results, is in the NASA Task Book and on each HRR gap page.

Clinical articles

For practical, clinic-facing guidance, see:

Evidence profile

Overall certainty: ◆◆◆◇ Moderate (proposed)
Evidence types: F · Flight dataE · Expert / operational / standards
Literature through: 2026-10-14
NASA source: Human Research Roadmap risk page (last published 05/13/25; read 2026-10-14)

Requirements referenced 2

Requirement	Title	Plain-language meaning
[V1 4005]–[V1 4010]	Sensorimotor Standards	Sensorimotor function must be maintained for critical tasks, with countermeasures and readaptation.
[V2 12045]	Nominal Timely Egress	Crew egress after landing must be expedited to protect crew health.

IDs as published in NASA-STD-3001 Vol. 1 Rev C (2023-09-15) and NASA-STD-3001 Vol. 2 Rev F (2026-07-14). NASA-STD-3001 binds NASA programs; it is not a regulation for commercial flights. Paraphrased. Standards quick reference.

References 6

NASA Human Research Roadmap. Risk record: “Risk of Altered Sensorimotor/Vestibular Function Impacting Critical Mission Tasks, Human Health, and Long-Term Health”. Accessed 2026-10-14. humanresearchroadmap.nasa.gov/Risks/?i=88 NASA E
NASA Human Research Program. Evidence report for the Sensorimotor risk (approved April 7, 2022). humanresearchroadmap.nasa.gov/evidence/reports/SM%20Evidence… NASA E
Antonsen EL, et al. Updates to the NASA human system risk management process for space exploration. NPJ Microgravity. 2023;9:72. doi:10.1038/s41526-023-00305-z PMID:37679359 Peer-reviewed E
Mulavara AP, et al. Locomotor function after long-duration space flight: effects and motor learning during recovery. Exp Brain Res. 2010;202(3):649–659. doi:10.1007/s00221-010-2171-0 PMID:20135100 Peer-reviewed F
Wood SJ, Paloski WH, Clark JB. Assessing sensorimotor function following ISS with computerized dynamic posturography. Aerosp Med Hum Perform. 2015;86(12 Suppl):A45–A53. doi:10.3357/AMHP.EC07.2015 PMID:26630195 Peer-reviewed F
Jones CW, et al. Molecular and physiological changes in the SpaceX Inspiration4 civilian crew. Nature. 2024;632:1155–1164. doi:10.1038/s41586-024-07648-x PMID:38862026 Peer-reviewed F

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