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The ISS Dynamic Lighting Schedule: An In-Flight Lighting Countermeasure to Facilitate Circadian Adaptation, Improve Sleep and Enhance Alertness and Performance on the International Space Station (NCC958HFP02801)
Principal Investigator
Research Area:
Human factors
Species Studied
Scientific Name: Homo sapiens Species: Human

Light exposure is a requirement for all space flight and base missions and careful consideration is required to provide light of sufficient quality and quantity to ensure adequate vision and to optimize the circadian, neuroendocrine, and neurobehavioral effects of light, and ultimately crew health and safety. The requirement to replace the out-of-date fluorescent lighting onboard the International Space Station (ISS) has provided an opportunity to re-fit the ISS with the latest in solid-state lighting technology which has the capability to provide light of varying spectrum, intensity, and pattern. While previous work has established blue and blue-enriched light as optimal to enhance circadian entrainment and alertness, final ground-based testing in high-fidelity analogs is required to develop guidelines for operational use prior to flight testing.

The proposed study will provide the ground-based data necessary to inform guidelines for flight testing the new lighting source, in time for the fluorescent light replacement in 2015. The proposal specifically targets lighting countermeasures to address circadian misalignment and performance decrements during a 'slam-shift,' which is a common requirement during Soyuz docking, and to enhance sleep and alertness during both 'slam-shift' and normal operations. Without such data, future recommendations for operational deployment of the Solid State Lighting Assemblies (SSLAs) will be suboptimal.

The Earth-based applications and commercialization potential of these studies are enormous. Electric lighting is ubiquitous and light can be used to improve alertness directly, thereby improving productivity and safety, and ultimately health. Anywhere where electric lighting is used, including schools, colleges, offices, factories, hospitals, care homes, residential homes, and transport and military applications, are potential beneficiaries. The 'slam-shifts' aboard the ISS, and the consequences to sleep, circadian rhythms, performance and health, are very similar to that experienced by many Americans who do shiftwork. The World Health Organization recently designated shiftwork that involves circadian 'desynchrony' as a probable carcinogen and shift-workers also have high rates of night-time accidents and injuries, cardiovascular disease, and diabetes. Similar lighting interventions could be deployed for night shift-workers using the same Dynamic Lighting Schedule (DLS) which would have the benefit of improving productivity and safety while also reducing energy use by using targeted light spectra that only provide the light needed.

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Ftouni S, Rahman SA, Crowley KE, Anderson C, Rajaratnam SM, and Lockley SW. Temporal dynamics of ocular indicators of sleepiness across sleep restriction. Journal of Biological Rhythms. 2013. December; 28(6):412-24. []

Rahman SA, Flynn-Evans EE, Aeschbach D, Brainard GC, Czeisler CA, and Lockley SW. Diurnal spectral sensitivity of the acute alerting effects of light. Sleep. 2014. February 1; 37(2):271-81. []

Circadian rhythm
Eye movements
Reaction time
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Data Information
Data Availability
Archiving in progress. Data is not yet available for this experiment.

Circadian desynchrony
Light exposure
Postural changes
Sleep loss
Sleep phase resetting

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Ground 05/01/2009 In Progress

Human Research Program (HRP) Human Research Roadmap (HRR) Information
Crew health and performance is critical to successful human exploration beyond low Earth orbit. The Human Research Program (HRP) investigates and mitigates the highest risks to human health and performance, providing essential countermeasures and technologies for human space exploration. Risks include physiological and performance effects from hazards such as radiation, altered gravity, and hostile environments, as well as unique challenges in medical support, human factors, and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify the approach and research activities planned to address these risks, which are assigned to specific Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.

The Human Research Roadmap is located at:

+ Click here for information of how this experiment is contributing to the HRP's path for risk reduction.

Additional Information
Managing NASA Center
National Space Biomedical Research Institute (NSBRI)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
Proposal Source
2011 Crew Health NNJ11ZSA002NA