NOTE: End date changed to 08/31/2024 per L. Juliette/JSC (Ed., 4/10/23)

NOTE: End date changed to 08/31/2023 per NSSC information (Ed., 10/13/22)

NOTE: End date changed to 08/31/2022 per NSSC information (Ed., 8/31/21)

NOTE: End date changed to 08/31/2021 per NSSC information (Ed., 2/3/21)

NOTE: End date changed to 12/31/2020 per D. Risin/HRP/NSSC information (Ed., 09/14/2020)

NOTE: End date changed to 09/30/2020 per NSSC information (Ed., 04/27/2020)

NOTE: End date changed to 03/31/2020 per NSSC information (Ed., 9/3/19)

NOTE: End date changed to 11/30/2019 per NSSC information (Ed., 10/11/18)

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Originally, the International Space Station (ISS) used General Luminaire Assemblies (GLAs) that housed fluorescent lamps for illuminating the astronauts' working and living environments. NASA determined that, beginning in 2016, the GLAs would be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members' working and living quarters, and 2) serve as a lighting countermeasure for crewmembers' circadian and sleep disruption. NASA ordered and received for a set of SSLAs intended to have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women's Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures are testing the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, the initial SSLA was installed on ISS in 2016. Since then, a total of 82 SSLAs have been installed on ISS, bringing the total retrofit to 96% replacement of GLAs on the US portion of ISS. Since the onset of the SSLA retrofit, the investigators started the inflight ISS study to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

This research was designed to address NASA's Program Requirements Document (PRD) Risk: "Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload" and Integrated Research Plan (IRP) Gap Sleep5: "We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations." The results of this research also specifically address other high priority risks of the Human Factors and Behavioral Performance Element, including the Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders, and the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate such risks in future Exploration missions. Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes. As of November 2021, the Human Research Program risks and gaps have since been revised per more recent IRPs; see above for the current noted Risks and Gaps and the Human Research Roadmap: https://humanresearchroadmap.nasa.gov/

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

Three ground analog studies and an International Space Station (ISS) flight study were completed successfully in this project.

In the five-day analog study, which enrolled 25 astronaut-aged participants, preliminary results found that in the evening the dynamic lighting evoked a significantly earlier onset of plasma melatonin, as hypothesized. Consistent with that finding, there was a nonsignificant trend for dynamic lighting to influence the circadian phase angle between acrophase of urinary aMT6 and scheduled wake time. There were no effects of evening lighting on subjective alertness as measured by the Karolinska sleepiness scale (KSS) or of sleep as assessed by actigraphy, as well as no effects of lighting on morning neurocognition as tested by the digit symbol substitution test (DSST).

Turning to the acute analog visual performance testing in the high-fidelity replica crew sleeping quarters, a cohort of 8 astronaut-aged participants showed significant effects of dim, presleep lighting on visual performance, as assessed by the Numerical Verification Test (NVT) and a significant decrease in color vision under nominal and dim presleep lighting as tested by the Farnsworth-Munsell 100 Hue Color Vision Test (FM100). Tests on a separate cohort of 8 astronaut-aged subjects showed a significant decrease in color vision under nominal and dim presleep lighting as scored by the FM100 in both fixed-head and freely-moving head positions.

Aboard the ISS, over 600,000 lighting measures were taken across all ISS nodes and modules. The Solid State Lighting Assemblies (SSLAs) inflight were stable in spectral emissions across all settings for nearly three years. The ISS interior lighting retrofit led to quite varied lighting conditions across the 7 astronauts studied, essentially creating 7 case studies.

There were no significant differences in aMT6s acrophases between the current and historical crewmembers during the inflight nominal schedule. When assessed by lighting condition, sleep duration was significantly longer and wakefulness after sleep onset (WASO) was significantly shorter during the current SSLA lighting as compared to the historical General Lighting Assemblies (GLA) lighting. The psychomotor vigilance task (PVT) reaction time was significantly quicker under nominal versus shifted schedules, but reaction time was not different between current SSLA and historic GLA conditions. There were no significant differences in any comparison for PVT lapses. With all data combined, there was a trend for an increase in sleep duration and a decrease in WASO as the number of SSLA installations increased. Although not statistically significant, there were indications of improvement aMT6s acrophase approaching normal timing, quicker reaction times, and fewer attentional failures as more SSLAs were installed. Visual testing preflight, inflight, and postflight on astronauts showed a significant decrease in color vision under nominal and dim presleep lighting in preflight and postflight, with a nonsignificant trend for a decrease in color vision inflight under dim presleep lighting inflight. Similar significant decreases in visual performance relative to presleep light exposures were detected.

NOTE: End date changed to 08/31/2024 per L. Juliette/JSC (Ed., 4/10/23)

NOTE: End date changed to 08/31/2023 per NSSC information (Ed., 10/13/22)

NOTE: End date changed to 08/31/2022 per NSSC information (Ed., 8/31/21)

NOTE: End date changed to 08/31/2021 per NSSC information (Ed., 2/3/21)

NOTE: End date changed to 12/31/2020 per D. Risin/HRP/NSSC information (Ed., 09/14/2020)

NOTE: End date changed to 09/30/2020 per NSSC information (Ed., 04/27/2020)

NOTE: End date changed to 03/31/2020 per NSSC information (Ed., 9/3/19)

NOTE: End date changed to 11/30/2019 per NSSC information (Ed., 10/11/18)

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Originally, the International Space Station (ISS) used General Luminaire Assemblies (GLAs) that housed fluorescent lamps for illuminating the astronauts' working and living environments. NASA determined that, beginning in 2016, the GLAs would be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members' working and living quarters, and 2) serve as a lighting countermeasure for crewmembers' circadian and sleep disruption. NASA ordered and received for a set of SSLAs intended to have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women's Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures are testing the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, the initial SSLA was installed on ISS in 2016. Since then, a total of 82 SSLAs have been installed on ISS, bringing the total retrofit to 96% replacement of GLAs on the US portion of ISS. Since the onset of the SSLA retrofit, the investigators started the inflight ISS study to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

This research was designed to address NASA's Program Requirements Document (PRD) Risk: "Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload" and Integrated Research Plan (IRP) Gap Sleep5: "We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations." The results of this research also specifically address other high priority risks of the Human Factors and Behavioral Performance Element, including the Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders, and the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate such risks in future Exploration missions. Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes. As of November 2021, the Human Research Program risks and gaps have since been revised per more recent IRPs; see above for the current noted Risks and Gaps and the Human Research Roadmap: https://humanresearchroadmap.nasa.gov/

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

Ground-Based Analog Study: This study aims to test the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled five-day inpatient study using astronaut-aged volunteers, we tested the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18 h wake: 6 h sleep) will improve visual performance, circadian entrainment, the onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and NASA. Previously, NASA and National Space Biomedical Research Institute (NSBRI) funded the PI and Co-PI to develop a high-fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects were able to be upright in this CQ and work, read, or use a computer just as crewmembers do aboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronaut., 2013; Brainard et al., Curr. Opin. Pulm. Med., 2016). The SSLAs were each adjusted for their spectral output to be as close as possible to NASA’s vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT) and luminance in candelas (cd) for three basic settings: 1) General Illumination: 4500 K SSLA white light, 210 cd; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-PIs determined that the 90 cd luminance at the crewmember’s eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in spaceflight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs aboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study included male and female volunteers in good physical and mental health with normal color vision. Volunteers were selected in the age range of astronauts (range 26-54 years). Prior to admission to the laboratory, subjects were asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 days. Twenty-eight subjects completed the screening process and were randomly assigned into a lighting condition of either dynamic (N=16) or static (N=12) lighting. Among those subjects, 19 were male, and 9 were female (age range 26 – 53 years). Twenty-five of these subjects successfully completed the entire five-day study. The data gathered from this first study run include a successful collection of complete pre-study actigraphy and inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five-day inpatient study (over 6,700 total). In addition, 95 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study (2,375 total). Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Melatonin contents of 548 plasma samples from 25 participants who completed a full study run have been analyzed. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6-sulfatoxymeltonin measures match similar or identical tests that were used aboard ISS during the flight study. Portions of data from this study have been uploaded to the NASA Large File Transfer service.

The testing of visual performance and color vision under different SSLA light settings has been done separately from the five-day studies. Two separate cohorts of 8 healthy male and female astronaut-aged subjects have completed within-subjects study designs that test their visual performance and color vision. Complete reporting on the three analog studies has been made to NASA. Data analysis and development of manuscripts is ongoing.

ISS Flight Study: The aims of this study were to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers aboard ISS missions. Specifically, we assessed the acceptability, use and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study tested the hypotheses that, compared to current static daily fluorescent lighting of General Illumination only, the Dynamic Lighting Schedule protocol would maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a "slam-shift," improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals were obtained from NASA and Partners Healthcare for the flight study. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment. Subsequently, the Human Research Program (HRP) Science Management Panel selected this study for flight on 9/3/15. A total of eight crew members consented to participate in the flight study. Seven astronauts have completed pre-flight, in-flight, and post-flight testing. As of September 2022, 82 SSLAs have been successfully installed, providing a 96% retrofit of the ISS.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the remnants of the original ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity is maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. Working with the study collaborators, ISSMP selected and deployed the meter for the flight study on ISS. A total of 37 sets of lighting measures have been taken by crewmembers and transmitted from ISS to the study team on Earth.

Considerable work between the study collaborators and the hardware group of ISSMP has gone into making flight-worthy versions of visual performance and color vision tests. Those tests were used successfully on the ISS. The Lanthony Desaturated 15-Hue test is the method used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples were identified from previous flight studies and used as the control data in the flight study. Seven crewmembers have completed all post-flight data collection, including actiwatch/sleep logs, cognition, urine sampling, and visual testing. The urine samples were returned to Earth and analyzed for 6-sulfatoxymelatonin. After the completion of their flight mission, each of the seven crewmembers met personally with one or two representatives from BWH and TJU for debriefing at JSC. Complete reporting on this ISS flight study has been made to NASA. Data analysis and development of manuscripts are ongoing.

New Analog Study: As described above, the original objectives of doing an analog ground study and an ISS flight study have been successfully completed and reported to NASA. The analog study data showed that the new SSLA developed for re-lamping the ISS can facilitate the onset of evening melatonin secretion, an important component of sleep physiology. This benefit of the Pre-sleep SSLA light setting, however, comes at the cost of significantly reducing color vision. Data from the analog study demonstrated that color vision was significantly reduced under the Pre-sleep setting. Similarly, data collected ISS flight study also showed color vision was significantly reduced under the Pre-sleep setting. There are many color-sensitive tasks during space flight, such as the hydrazine test, electrical wiring, and the like. Further, color coding is used in warnings, reminders, and crewmember manuals. Crewmembers often read manuals during the pre-sleep period to prepare for the next day’s operations.

Human Factors and Behavioral Performance Element provided augmentation funding to support a small study (N=8) to test the hypothesis that, compared to the current ISS Pre-sleep light intensity, a modified spectrum and/or an increased Pre-sleep light intensity will still permit an earlier melatonin onset while improving crewmember color vision. The COVID-19 pandemic, however, caused a cessation of our program’s human subject testing for two and a half years. Rcently, we have successfully restocked expired medical supplies, restaffed, and are recruiting participants for this new analog study. Enrollment of our first NASA participant is poised to start no sooner than November 2022.

This study specifically addresses high-priority risks of the Human Factors and Behavioral Performance Element, including the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate risks in programs such as Artemis and Gateway. If successful, the study will inform the NASA Technical Standard 3001 for the lighting of future space vehicles and habitats.

References: Brainard GC, Coyle W, Ayers M, Kemp J, Warfield B, Maida J, Bowen C, Bernecker C, Lockley SW, and Hanifin JP. Solid-state lighting for the International Space Station: Tests of visual performance and melatonin regulation. Acta Astronaut. 2013 Nov;92:21-8.

Brainard GC, Barger LK, Soler RR, and Hanifin JP. The development of lighting countermeasures for sleep disruption and circadian misalignment during spaceflight. Current Opinion in Pulmonary Medicine. 2016;22:535-44.

NASA. ISS Interior Solid State Lighting Assembly (SSLA) specification, revision C. May 2013;S684-13489.

NOTE: End date changed to 8/31/2022 per NSSC information (Ed., 8/31/21)

NOTE: End date changed to 8/31/2021 per NSSC information (Ed., 2/3/21)

NOTE: End date changed to 12/31/2020 per D. Risin/HRP/NSSC information (Ed., 09/14/2020)

NOTE: End date changed to 09/30/2020 per NSSC information (Ed., 04/27/2020)

NOTE: End date changed to 03/31/2020 per NSSC information (Ed., 9/3/19)

NOTE: End date changed to 11/30/2019 per NSSC information (Ed., 10/11/18)

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts' working and living environments. NASA has determined that, beginning in 2016, the GLAs would be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members' working and living quarters, and 2) serve as a lighting countermeasure for crewmembers' circadian and sleep disruption. NASA ordered and received for a set of SSLAs intended to have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women's Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures are testing the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, the initial SSLA was installed on ISS in 2016. Since then, a total of 51 SSLAs have been installed on ISS, bringing the total retrofit to 60% replacement of GLAs on the US portion of ISS. Since the onset of the SSLA retrofit, the investigators have started the inflight ISS study to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

This research addresses NASA's Program Requirements Document (PRD) Risk: "Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload" and Integrated Research Plan (IRP) Gap Sleep5: "We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations." The results of this research also specifically address other high priority risks of the Human Factors and Behavioral Performance Element, including the Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders, and the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate such risks in future Exploration missions. Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes. [Ed. note November 2021: Human Research Program risks and gaps have since been revised per more recent IRPs; see above noted Risks and Gaps and the Human Research Roadmap: https://humanresearchroadmap.nasa.gov/ ]

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

In the current study, we have completed the initial assessments of the stability and utility of this new lighting system and begun to measure its physiological impact on circadian phase, sleep, and performance. There were no significant differences in aMT6s acrophases between the current and historical crewmembers during the in-flight nominal schedule but there was a trend for a significantly later phase in the historical versus the current group by nearly 4 hours. Consequently, as expected, sleep duration was higher and reaction time was quicker under the normal versus the shifted schedule. When correlated with the proportion of SSLA units installed, the increase in sleep duration and reduction in waketime after sleep on set (WASO) correlated with a higher number of SSLA units. The asMT6s acrophase time also approached a more normal phase and reduced in variability and reaction time, and attentional failures were less apparent.

While preliminary, these results are encouraging with evidence for greater normalization of circadian phase, longer sleep, and quicker reaction times under the new lighting that appear to get better as the proportion of SSLA units installed increases. Further work remains, however, as none of the crewmembers reported here experienced the ISS environment with more than 75% of the SSLA installation complete (and most had much less exposure) and therefore the benefits of a completely retrofitted environment have not been studied. Moreover, the amount by which work schedules were shifted in the current crewmembers was modest compared to historical schedules and therefore the efficacy of the lighting to alleviate circadian misalignment and sleep loss following more challenging schedule changes is unknown.

NOTE: End date changed to 8/31/2022 per NSSC information (Ed., 8/31/21)

NOTE: End date changed to 8/31/2021 per NSSC information (Ed., 2/3/21)

NOTE: End date changed to 12/31/2020 per D. Risin/HRP/NSSC information (Ed., 09/14/2020)

NOTE: End date changed to 09/30/2020 per NSSC information (Ed., 04/27/2020)

NOTE: End date changed to 03/31/2020 per NSSC information (Ed., 9/3/19)

NOTE: End date changed to 11/30/2019 per NSSC information (Ed., 10/11/18)

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts' working and living environments. NASA has determined that, beginning in 2016, the GLAs would be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members' working and living quarters, and 2) serve as a lighting countermeasure for crewmembers' circadian and sleep disruption. NASA ordered and received for a set of SSLAs intended to have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women's Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures are testing the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, the initial SSLA was installed on ISS in 2016. Since then, a total of 51 SSLAs have been installed on ISS, bringing the total retrofit to 60% replacement of GLAs on the US portion of ISS. Since the onset of the SSLA retrofit, the investigators have started the inflight ISS study to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

This research addresses NASA's Program Requirements Document (PRD) Risk: "Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload" and Integrated Research Plan (IRP) Gap Sleep5: "We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations." The results of this research also specifically address other high priority risks of the Human Factors and Behavioral Performance Element, including the Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders, and the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate such risks in future Exploration missions. Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

Ground Based Analog Study: This study aims tested the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled 5-day inpatient study using astronaut-aged volunteers, we tested the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18 h wake: 6 h sleep) will improve visual performance, circadian entrainment, onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and NASA. Previously, NASA and National Space Biomedical Research Institute (NSBRI) funded the PI and Co-PI to develop a high fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects were able to be upright in this CQ and work, read, or use a computer just as crewmembers do onboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronaut., 2013; Brainard et al., Curr. Opin. Pulm. Med., 2016). In that earlier work, however, only a single subject could be studied at a time in the facility. In the current work, a second high-fidelity recumbent CQ was built and installed in the test facility enabling us to study up to two subjects at a time, with the intent of improving our speed for acquiring data in the analog facility. The SSLAs were each adjusted for their spectral output to be as close as possible to the NASA’s vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT or K) and luminance in candelas (cd) for three basic settings: 1) General Illumination: 4500 K SSLA white light, 210 cd; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-PIs determined that the 90 cd luminance at crewmember’s eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in spaceflight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs onboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study included male and female volunteers in good physical and mental health with normal color vision. Volunteers were selected in the age range of astronauts (range 26-54 years). Prior to admission to the laboratory, subjects were asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 days. Over 550 subjects expressed interest in participating in this study. Approximately half of those individuals were not eligible based on phone interviews. Among those who were potentially eligible, 70 signed consent paperwork. Twenty-eight of those subjects completed the screening process and were randomly assigned into a lighting condition of either dynamic (N=16) or static (N=12) lighting. Among those subjects, 19 were male and 9 were female (age range 26 – 53 years). Twenty-five of these subjects successfully completed the entire five day study.

The data gathered from this first study run include successful collection of complete pre-study actigraphy, and inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five day inpatient study (over 6,700 total). In addition, 95 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study (2,375 total). Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Melatonin contents of 548 plasma samples from 25 participants who completed a full study run have been analyzed. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6-sulfatoxymeltonin measures match similar or identical tests that were used onboard ISS during the flight study. Subject recruitment and enrolling is now completed. Data analysis is in process on the numerous dependent variables from the 5-day study. Portions of data from this study have been uploaded to the NASA Large File Transfer service.

The testing of visual performance and color vision under different SSLA light settings has been done separately from the five day studies. Two separate cohorts of 8 healthy male and female, astronaut-aged subjects have completed within-subjects study designs that test their visual performance and color vision. The data from each of these studies is being analyzed.

ISS Flight Study: The aims of this study are to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers onboard ISS missions. Specifically, we are assessing the acceptability, use and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study will test the hypotheses that, compared to current static daily fluorescent lighting of General Illumination only, the Dynamic Lighting Schedule protocol will maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a ‘slam-shift,’ improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals were obtained from NASA and Partners Healthcare for the flight study. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment. Subsequently, the Human Research Program (HRP) Science Management Panel selected this study for flight on 9/3/15. The first ISSMP teleconference was held on 9/30/15 involving representatives from JSC’s ISSMP, BWH, and TJU. This teleconference was held monthly through the set up and running of the study. A total of eight crew members consented to participate in the flight study. Seven astronauts have completed pre-flight, in-flight, and post-flight testing. As of October, 2020, 77 SSLAs have been successfully installed providing a 92% retrofit of the ISS.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the remains of the original ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity are maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. Working with the study collaborators, ISSMP has selected and deployed the meter for the flight study on ISS. A total of 37 sets of lighting measures have been taken by crewmembers and transmitted from ISS to the study team on Earth.

Considerable work between the study collaborators and the hardware group of Research Operations & Integration (ROI) element [Ed. note October 2020: ROI was formerly ISSMP; element change in 2019) has gone into making flight worthy versions of visual performance and color vision tests. Those tests were used successfully on the ISS. The Lanthony Desaturated 15-Hue test is the method to be used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples have been identified from previous flight studies that will act as the control data in the flight study. Discussions are ongoing about data sharing for these historical data. Through September 2019, seven crewmembers have completed all post-flight data collection, including actiwatch/sleep logs, cognition, urine sampling, and visual testing. Data are being analyzed on these dependent measures. The urine samples have been returned to Earth and will be analyzed for 6-sulfatoxymelatonin at BWH in the near range. After completion of their flight mission, each of the seven crewmembers met personally with one or two representatives from BWH and TJU for debriefing at JSC. The project is scheduled to end on December 31, 2020. It is anticipated that data analysis and development of manuscripts will continue after that end date.

References:

Brainard GC, Coyle W, Ayers M, Kemp J, Warfield B, Maida J, Bowen C, Bernecker C, Lockley SW, Hanifin JP (2013) Solid-state lighting for the International Space Station: tests of visual performance and melatonin regulation. Acta Astronautica 92:21–28.

Brainard, GC, Barger LK, Soler RR and Hanifin JP (2016) The development of lighting countermeasures for sleep disruption and circadian misalignment during spaceflight. Current Opinion in Pulmonary Medicine, 22(6):535-544.

NASA Revision C, S684-13489, (2013) ISS Interior Solid State Lighting Assembly (SSLA) Specification, Revision A, July 2011, S684-13489, Johnson Space Center, Houston, pp 1–60.

NOTE: End date changed to 11/30/2019 per NSSC information (Ed., 10/11/18)

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts' working and living environments. NASA has determined that, beginning in 2016, the GLAs would be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members' working and living quarters, and 2) serve as a lighting countermeasure for crewmembers' circadian and sleep disruption. NASA ordered and received for a set of SSLAs intended to have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women's Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures are testing the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, the initial SSLA was installed on ISS in 2016. Since then, a total of 51 SSLAs have been installed on ISS, bringing the total retrofit to 60% replacement of GLAs on the US portion of ISS. Since the onset of the SSLA retrofit, the investigators have started the inflight ISS study to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

This research addresses NASA's Program Requirements Document (PRD) Risk: "Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload" and Integrated Research Plan (IRP) Gap Sleep5: "We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations." The results of this research also specifically address other high priority risks of the Human Factors and Behavioral Performance Element, including the Risk of Adverse Cognitive or Behavioral Conditions and Psychiatric Disorders, and the Risk of an Incompatible Habitat Design. Appropriately designed lighting systems will serve as a countermeasure to mitigate such risks in future Exploration missions. Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

Ground Based Analog Study: This study aims to test the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled 5-day inpatient study using astronaut-aged volunteers, we are testing the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18 h wake: 6 h sleep) will improve visual performance, circadian entrainment, onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and NASA. Previously, NASA and National Space Biomedical Research Institute (NSBRI) funded the Principal Investigator (PI) and Co-PI to develop a high fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects were able to be upright in this CQ and work, read, or use a computer just as crewmembers do onboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronaut., 2013; Brainard et al., Curr. Opin. Pulm. Med., 2016). In that earlier work, however, only a single subject could be studied at a time in the facility. In the current work, a second high-fidelity recumbent CQ was built and installed in the test facility enabling us to study up to two subjects at a time, to improve our speed for acquiring data in the analog facility. The SSLAs were each adjusted for their spectral output to be as close as possible to the NASA's vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT or K) and luminance in candelas (cd) for three basic settings: 1) General Illumination: 4500 K SSLA white light, 210 cd; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-PIs have determined that the 90 cd luminance at crewmember's eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in spaceflight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs onboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study includes male and female volunteers in good physical and mental health with normal color vision. Volunteers are selected in the age range of astronauts (range 26-54 years). Prior to admission to the laboratory, subjects are asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 to 14 days. In August 2015, study recruitment was initiated. Over 550 subjects expressed interest in participating in this study. Approximately half of those individuals were not eligible based on phone interviews. Among those who were potentially eligible, 70 signed consent paperwork. Twenty-eight of those subjects completed the screening process and were randomly assigned into a lighting condition of either dynamic (N=16) or static (N=12) lighting. Among those subjects, 19 were male and 9 were female (age range 26 - 53 years). Twenty-five of these subjects successfully completed the entire five day study.

The data gathered from this first study run include successful collection of complete pre-study actigraphy, and inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five day inpatient study (over 6,700 total). In addition, 95 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study (2,375 total). Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Melatonin contents of 548 plasma samples from 25 participants who completed a full study run have been analyzed. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6 sulfatoxymeltonin measures match similar or identical tests that will be used onboard ISS during the flight study. Subject recruitment and enrolling has been stopped at this time. Data analysis is in process on the numerous dependent variables from the 5-day study. Portions of data from this study have been uploaded to the NASA Large File Transfer service.

The testing of visual performance and color vision under different SSLA light settings has been done separately from the five day studies. Two separate cohorts of 8 healthy male and female, astronaut-aged subjects have completed within-subjects study designs that test their visual performance and color vision. The data from each of these studies is being analyzed.

ISS Flight Study: Compared to the analog study, the flight study is at an earlier stage. The aims of this study are to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers onboard ISS missions. Specifically, we will assess the acceptability, use and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study will test the hypotheses that, compared to current static daily fluorescent lighting of General Illumination only, the Dynamic Lighting Schedule protocol will maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a 'slam-shift', improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals have been obtained from NASA and Partners Healthcare for the flight study. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment on 8/8/15. Subsequently, the Human Research Program (HRP) Science Management Panel selected this study for flight on 9/3/15. The first ISSMP teleconference was held on 9/30/15 involving representatives from JSC's ISSMP, BWH, and TJU. Currently, this teleconference is held monthly. To date, seven crew members have consented to participate in the flight study. The first three astronauts have completed pre-flight, in-flight, and post-flight testing. The other four consented crewmembers are in process in various phases of pre-flight, in-flight, and post-flight testing. Fifty-one SSLAs have been successfully installed in the ISS.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the current ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity are maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. Working with the study collaborators, ISSMP has selected and purchased the meter that is being used for the flight study. To date, 23 sets of lighting measures have been taken by crewmembers and transmitted from ISS to the study team on Earth.

Considerable work between the study collaborators and the hardware group of ISSMP has gone into making flight worthy versions of visual performance and color vision tests. These tests are now complete and are being used on the ISS. The Lanthony Desaturated 15-Hue test is the method to be used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. Additional planning for the flight study is ongoing with regular meetings with NASA personnel. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples have been identified from previous flight studies that will act as the control data in the flight study. Discussions are ongoing about data sharing for these historical data.

References

Brainard GC, Coyle W, Ayers M, Kemp J, Warfield B, Maida J, Bowen C, Bernecker C, Lockley SW and Hanifin JP (2013) Solid-state lighting for the International Space Station: tests of visual performance and melatonin regulation. Acta Astronautica 92:21-28.

Brainard GC, Barger LK, Soler RR and Hanifin JP (2016) The development of lighting countermeasures for sleep disruption and circadian misalignment during spaceflight. Curr Opin Pulm Med 22:535-544.

NOTE: End date changed to 11/30/2018 per NSSC information (Ed., 12/13/17)

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts’ working and living environments. NASA has determined that, beginning in 2016, the GLAs will be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members’ working and living quarters, and 2) serve as a lighting countermeasure for crewmembers’ circadian and sleep disruption. NASA has now placed an order for a set of SSLAs to be manufactured that will have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women’s Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures will test the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, once the new SSLAs are deployed on ISS in 2016, the investigators plan to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

The proposed research addresses NASA’s Program Requirements Document (PRD) Risk: “Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload” and Integrated Research Plan (IRP) Gap Sleep5: “We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations.” Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.

References

Dijk DJ, Neri DF, Wyatt JK, Ronda JM, Riel E, A. R-D, Hughes RJ, Elliott AR, Prisk GK, West JB and Czeisler CA (2001) Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights. Am J Physiol 281:R1647-R1664.

McPhee J and Charles J, eds. 2010. Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program. NASA SP-2009-3405 edition.

Barger LK, Flynn-Evans EE, Kubey A, Walsh L, Ronda JM, Wang W, Wright KP and Czeisler CA (2014) Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study. Lancet Neurology 13:904-912.

Flynn-Evans EE, Barger LK, Kubey AA, Sullivan JP and Czeisler CA (2016) Circadian misalignment affects sleep and medication use before and during spaceflight. npj Microgravity 2:15019; doi:15010.11038/npjmgrav.12015.15019.

Ground Based Analog Study: This study aims to test the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled 5-day inpatient study using astronaut-aged volunteers, we are testing the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18 h wake: 6 h sleep) will improve visual performance, circadian entrainment, onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and NASA. Previously, NASA and National Space Biomedical Research Institute (NSBRI) funded the PI and Co-PI to develop a high fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects were able to be upright in this CQ and work, read, or use a computer just as crewmembers do onboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronaut., 2013; Brainard et al., Curr. Opin. Pulm. Med., 2016). In that earlier work, however, only a single subject could be studied at a time in the facility. In the current work, a second high-fidelity recumbent CQ was built and installed in the test facility enabling us to study up to two subjects at a time, to improve our speed for acquiring data in the analog facility. The SSLAs were each adjusted for their spectral output to be as close as possible to the NASA’s vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT or K) and luminance in candelas (cd) for three basic settings: 1) General Illumination: 4500 K SSLA white light, 210 cd ; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd ; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-Principal Investigators (Co-PIs) have determined that the 90 cd luminance at crewmember’s eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in spaceflight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs onboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study includes male and female volunteers in good physical and mental health with normal color vision. Volunteers are selected in the age range of astronauts (range 26-54 years). Prior to admission to the laboratory, subjects are asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 to 14 days. In August 2015, study recruitment was initiated. To date, over 550 subjects have expressed interest in participating in this study. Approximately half of those individuals were not eligible based on phone interviews. Among those who were potentially eligible, 70 have signed consent paperwork. Twenty-eight of those subjects completed the screening process and were randomly assigned into a lighting condition of either dynamic (N=16) or static (N=12) lighting. Among those subjects, 19 were male and 9 were female (age range 26 – 53 years). Twenty-five of these subjects successfully completed the entire five day study.

The data gathered from this first study run include successful collection of complete pre-study actigraphy, inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five day inpatient study (over 6,700 total). In addition, 95 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study (2,375 total). Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Melatonin contents of 548 plasma samples from 25 participants who completed a full study run have been analyzed. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6 sulfatoxymeltonin measures match similar or identical tests that will be used onboard ISS during the flight study. Subject recruitment and enrolling has been stopped at this time. Data analysis is in process on the numerous dependent variables from the 5-day study.

The testing of visual performance and color vision under different SSLA light settings has been done separately from the five day studies. Two separate cohorts of 8 healthy male and female, astronaut-aged subjects have completed within-subjects study designs that test their visual performance and color vision. The data from each of these studies is being analyzed.

ISS Flight Study: Compared to the analog study, the flight study is at an earlier stage. The aims of this study are to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers onboard ISS missions. Specifically, we will assess the acceptability, use and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study will test the hypotheses that, compared to current static daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol will maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a ‘slam-shift’, improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals have been obtained from NASA and Partners Healthcare for the flight study. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment on 8/8/15. Subsequently, the Human Research Program (HRP) Science Management Panel selected this study for flight on 9/3/15. The first ISSMP teleconference was held on 9/30/15 involving representatives from JSC’s ISSMP, BWH, and TJU. Currently, this teleconference is held monthly. To date, five crew members have consented to participate in the flight study. The first astronaut has completed pre-flight and in-flight testing and is now in process on post-flight testing. Two more crewmembers have completed pre-flight testing and are active in in-flight testing. Twenty seven SSLAs have been successfully installed the ISS.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the current ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity are maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. Working with the study collaborators, ISSMP has selected and purchased the meter that will be used for the flight study. To date, 9 sets of lighting measures have been taken by crewmembers and transmitted from ISS to the study team on Earth.

Considerable work between the study collaborators and the hardware group of ISSMP has gone into to making flight worthy versions of visual performance and color vision tests. These tests are now complete and are being used on ISS. The Lanthony Desaturated 15-Hue test is the method to be used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. Additional planning for the flight study is ongoing with regular meetings with NASA personnel. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples have been identified from previous flight studies that will act as the control data in the flight study. Discussions are ongoing about data sharing for these historical data.

References

Brainard GC, Coyle W, Ayers M, Kemp J, Warfield B, Maida J, Bowen C, Bernecker C, Lockley SW and Hanifin JP (2013) Solid-state lighting for the International Space Station: tests of visual performance and melatonin regulation. Acta Astronautica 92:21-28.

Brainard GC, Barger LK, Soler RR and Hanifin JP (2016) The development of lighting countermeasures for sleep disruption and circadian misalignment during spaceflight. Curr Opin Pulm Med 22:535-544.

NOTE: Element change to Human Factors & Behavioral Performance; previously Behavioral Health & Performance (Ed., 1/17/17)

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts’ working and living environments. NASA has determined that, beginning in 2016, the GLAs will be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members’ working and living quarters, and 2) serve as a lighting countermeasure for crewmembers’ circadian and sleep disruption. NASA has now placed an order for a set of SSLAs to be manufactured that will have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women’s Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures will test the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, once the new SSLAs are deployed on ISS in 2016, the investigators plan to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human spaceflight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

The proposed research addresses NASA’s Program Requirements Document (PRD) Risk: “Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload” and Integrated Research Plan (IRP) Gap Sleep5: “We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations.” Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.

Ground Based Analog Study: This study aims to test the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled 5-day inpatient study using astronaut-aged volunteers, we are testing the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18 h wake: 6 h sleep) will improve visual performance, circadian entrainment, onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and JSC. Previously, NASA and National Space Biomedical Research Institute (NSBRI) funded the PI and Co-PI to develop a high fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects are able to be upright in this CQ and work, read, or use a computer just as crewmembers do onboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronautica, 2013). In that earlier work, however, only a single subject could be studied at a time in the facility. In the current work, a second high-fidelity recumbent CQ was built and installed in the test facility enabling us to study up to two subjects at a time, to improve our speed for acquiring data in the analog facility. The SSLAs were each adjusted for their spectral output to be as close as possible to the NASA’s vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT or K) and luminance in candelas (cd) for three basic settings: 1) General Illumination: 4500 K SSLA white light, 210 cd ; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd ; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-PIs have determined that the 90 cd luminance at crewmember’s eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in spaceflight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs onboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study includes male and female volunteers in good physical and mental health with normal color vision. Volunteers are selected in the age range of astronauts (range 26-54 years). Prior to admission to the laboratory, subjects are asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 to 14 days. In August 2015, study recruitment was initiated. To date, 447 subjects have expressed interest in participating in this study. Approximately half of those individuals were not eligible based on phone interviews. Among those who were potentially eligible, 45 have signed consent paperwork. Sixteen of those subjects completed the screening process and were randomly assigned into their lighting condition of either dynamic (N=9) or static (N=7) lighting. Among those subjects, 12 were male and 4 were female (age range 28 – 54 years). Thirteen subjects successfully completed the entire five day study. The next study is scheduled to begin on 10/3/16.

The data gathered from this first study run include successful collection of complete pre-study actigraphy, inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five day inpatient study (2,144 total). In addition, 96 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study (768 total). Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Melatonin contents of 192 plasma samples from 8 participants who completed a full study run have been analyzed. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6 sulfatoxymeltonin measures match similar or identical tests that will be used onboard ISS during the flight study. To date, no data analysis has been done as our effort is now being aimed at recruiting additional study subjects and running the five day studies. Finally, the testing of visual performance and color vision will be done separately from the five day studies when we receive SSLA units made by the ISS contractor early in 2016.

ISS Flight Study: Compared to the analog study, the flight study is at an earlier stage. The aims of this study are to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers onboard ISS missions. Specifically, we will assess the acceptability, use and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study will test the hypotheses that, compared to current static daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol will maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a ‘slam-shift’, improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals have been obtained from NASA and Partners Healthcare for the flight study. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment on 8/8/15. Subsequently, the Human Research Program (HRP) Science Management Panel selected this study for flight on 9/3/15. The first ISSMP teleconference was held on 9/30/15 involving representatives from JSC’s ISSMP, BWH, and TJU. Currently, this teleconference is held every two weeks. Three crew members have consented to participate in the flight study. The first astronaut is scheduled to begin pre-flight testing in the near range. Four SSLAs have been successfully delivered to the ISS.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the current ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity are maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. Working with the study collaborators, ISSMP has selected and purchased the specific meter that will be used for the flight study. Considerable work between the study collaborators and the hardware group of ISSMP has gone into to making flight worthy versions of visual performance and color vision tests. These tests are now complete and ready to be used on ISS. The Lanthany Desaturated 15-Hue test is the method to be used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. Additional planning for the flight study is ongoing with regular meetings with NASA personnel. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples have been identified from previous flight studies that will act as the control data in the flight study. Discussions are ongoing about data sharing for these historical data.

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts’ working and living environments. NASA has determined that, beginning in 2016, the GLAs will be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members’ working and living quarters, and 2) serve as a lighting countermeasure for crewmembers’ circadian and sleep disruption. NASA has now placed an order for a set of SSLAs to be manufactured that will have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women’s Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures will test the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, once the new SSLAs are deployed on ISS in 2016, the investigators plan to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human space flight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

The proposed research addresses NASA’s Program Requirements Document (PRD) Risk: “Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload” and Integrated Research Plan (IRP) Gap Sleep5: “We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations.” Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.

Ground Based Analog Study: This study aims to test the efficacy of lighting protocols for daily operations using Solid State Lighting Assemblies (SSLAs) in ISS CQs installed in laboratories at TJU. In a controlled 5-day inpatient study using astronaut-aged volunteers, we are testing the hypotheses that compared to the static, daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol for a typical ISS work day (18h wake: 6 h sleep) will improve visual performance, circadian entrainment, onset of melatonin production, sleep onset, sleep duration as well as morning alertness and performance. Separate human use protocols were submitted and approved by the Institutional Review Boards (IRBs) at TJU and JSC. Previously, NASA and the National Space Biomedical Research Institute (NSBRI) funded the PI and Co-PI to develop a high fidelity, in-laboratory analog environment to study the visual, biological, and behavioral effects of the SSLAs. Specifically, a high-fidelity replica of the ISS Crew Sleeping Quarters (CQ) was developed with precise replication of CQ volume, geometry, and surface reflectance with an SSLA providing illumination. Astronaut-aged study subjects are able to be upright in this CQ and work, read, or use a computer just as crewmembers do onboard the ISS. In addition, a second CQ was developed that allows subjects to be semi-recumbent during wakefulness in SSLA lighting or fully recumbent when sleeping in darkness. Data from controlled studies in these high fidelity in-laboratory analog conditions represent the only published ground-based human data on the efficacy of the SSLAs to date (Brainard et al., Acta Astronautica, 2013). In that earlier work, however, only a single subject could be studied at a time in the facility. In the current work, a second high-fidelity recumbent CQ was built and installed in the test facility enabling us to study up to two subjects at a time, significantly improving our speed for acquiring data in the analog facility. The SSLAs were each adjusted for their spectral output to be as close as possible to the NASA’s vendor requirements for ISS (NASA Revision C, S684-13489, 2013). These specifications include Correlated Color Temperature (CCT or K) and luminance in candelas (cd) for three basic settings:

1) General Illumination: 4500 K SSLA white light, 210 cd ; 2) Phase Shift/Alertness: 6500 K SSLA (blue-enriched) white light, 420 cd ; 3) Pre-Sleep: 2700 K SSLA (blue-depleted) white light, 90 cd.

Based on published and unpublished data, the Co-PIs have determined that the 90 cd luminance at crewmember’s eye level inside of a CQ would be too bright to serve as an effective Pre-Sleep countermeasure. This issue was discussed with our project management team at JSC on several occasions. It was determined that in space flight, the SSLA luminance could be lowered from 90 cd using a combination of SSLA dimming buttons and a cloth shade system that is currently used on the fluorescent lighting system in the CQs onboard ISS. Based on a series of SSLA lighting measures and our prior pilot study in the CQs, we chose a Pre-Sleep luminance of 7.7 cd (20 lux at eye level) for our Pre-Sleep setting.

This study includes male and female volunteers in good physical and mental health with normal color vision. Volunteers are selected in the age range of typical astronauts (range 30-54 years). Prior to admission to the laboratory, subjects are asked to maintain a regular 8:16 h, sleep:wake schedule and wear a wrist-borne, non-invasive activity and light monitor for at least 10 to 14 days. In August 2015, study recruitment was initiated. To date, 52 subjects have expressed interest in participating in this study. Approximately half of those individuals were not eligible based on phone interviews. Among those who were potentially eligible, 8 have signed consent paperwork. Two of those subjects have completed the screening process and successfully completed the first five day study. Subjects were randomly assigned into their lighting condition of either dynamic or static lighting. One subject was male (53 years) and one subject was female (34 years). The next study is scheduled to begin on 10/5/15.

The data gathered from this first study run include successful collection of complete pre-study actigraphy, inpatient study actigraphy from each subject. A total of 268 neurocognitive and performance tests were collected from each subject across the five day inpatient study. In addition, 96 Karolinska sleepiness scales (KSS) were collected from each subject across the inpatient study. Complete sets of blood, saliva, and urine samples were collected from each subject for the measurement of melatonin and 6-sulfatoxymelatonin. Polysomnography (PSG) was used to monitor sleep states and wakefulness using electrodes placed on the scalp, face, chin, and chest. Electrodes were positioned according to the International 10-20 System. The actigraphy, neurocognitive, and performance tests and urinary 6 sulfatoxymeltonin measures match similar or identical tests that will be used onboard ISS during the flight study. To date, no data analysis has been done as our effort is now being aimed at establishing the second five day study run on 10/5/15. Finally, the testing of visual performance and color vision will be done separately from the five day studies when we receive SSLA units made by the ISS contractor early in 2016.

ISS Flight Study: Compared to the analog study, the flight study is at a nascent stage. The aims of this study are to test the efficacy of lighting protocols for daily operations using SSLAs for inflight crewmembers onboard ISS missions. Specifically, we will assess the acceptability, use, and operational impact of deployment of the Dynamic Lighting Schedule protocol on astronaut vision, sleep, alertness, circadian rhythms, and general well-being during ISS flight missions. This inflight study will test the hypotheses that, compared to current static daily lighting of General Illumination only, the Dynamic Lighting Schedule protocol will maintain acceptable visual performance and color discrimination for operational tasks, improve circadian entrainment, improve circadian adaptation following a sleep shift challenge such as a ‘slam-shift’, improve sleep duration and efficiency, and enhance wake-time alertness and cognitive performance.

Ethical approvals have been obtained from NASA and Partners Healthcare for the flight study. Discussions about how to manage the ethical approval application at Thomas Jefferson University are ongoing. The flight study successfully went through an ISS Medical Project (ISSMP) feasibility assessment on 8/8/15. Subsequently, the HRP Science Management Panel selected this study for flight on 9/3/15. The first weekly ISSMP teleconference was held on 9/30/15 involving representatives from JSC’s ISSMP, BWH and TJU.

This ISS flight study on crewmembers is a sophisticated human photobiological study. All photobiological studies, whether in spaceflight or on Earth, rely on precise characterization of the independent variable of the study: light. For this study, the relevant light stimulus is light emitted by the new SSLAs and the current ISS fluorescent lighting system. A spectrophotometer/irradiance meter is an essential tool for ensuring that consistent emission of light spectrum and light intensity are maintained during the inflight ISS research. The key measures for this flight study are light irradiance, illuminance, and spectral power distribution of the four settings of the SSLAs, as well as the single setting of the current fluorescent lights. ISSMP is now in the process of assessing which specific meter will be selected for flight. The Farnsworth-Munsell 15 Hue test (D15) is the method to be used for testing crewmember color discrimination under the different SSLA light settings compared to that of the current fluorescent lighting on ISS. The hardware group of ISSMP has been developing two prototypes of this visual test that can be used during flight. Additional planning for the flight study is ongoing with regular meetings with NASA personnel. Historical data of actigraphy, sleep logs, cognitive testing, and urine samples have been identified from previous flight studies that will act as the control data in the flight study. Discussions are ongoing about how to manage consent procedures and data sharing for these historical data.

Currently, the International Space Station (ISS) uses General Luminaire Assemblies (GLAs) that house fluorescent lamps for illuminating the astronauts’ working and living environments. NASA has determined that, beginning in 2016, the GLAs will be replaced with Solid-State Light Assemblies (SSLAs) containing Light Emitting Diodes (LEDs). Engineers at Kennedy Space Center developed a prototype Solid-State Lighting Assembly (SSLA) that was successfully installed onboard the ISS during ISS Expedition 18. The Principal Investigator and Co-Principal Investigator of the intended research worked with engineers, scientists, and managers from Johnson Space Center (JSC) to revise the SSLA specifications so that the new lighting units would have dual capacity to: 1) provide illumination for crew members’ working and living quarters, and 2) serve as a lighting countermeasure for crewmembers’ circadian and sleep disruption. NASA has now placed an order for a set of SSLAs to be manufactured that will have this dual capacity.

This research is comprised of a multidisciplinary collaboration between Thomas Jefferson University, Brigham and Women’s Hospital, and JSC to complete a ground-based study in a high fidelity analog of the crew sleeping quarters and daily living environment of the ISS. Specifically, standardized psychometric, physiological, and neurobehavioral measures will test the efficacy of light from the SSLAs to improve vision, circadian regulation, sleep, and performance in healthy astronaut-aged subjects. In addition, once the new SSLAs are deployed on ISS in 2016, the investigators plan to assess the acceptability, use, and impact of deployment of a dynamic lighting schedule aboard the ISS during operational flight missions on astronaut vision, sleep, alertness, circadian rhythms, and general well-being. Sleep, performance, and circadian rhythm data will be compared to those collected by their team and others during previous flight missions aboard ISS, in addition to surveillance of medical and psychological health in collaboration with mission flight surgeons. This project will generate quantitative data and knowledge for the benefit of crew health, habitability, environment, and human factors in the design of future human space flight vehicles and habitats. The project also will provide guidance for flight surgeons, flight psychologists, and astronauts to help optimize sleep and circadian regulation during space exploration missions.

The proposed research addresses NASA’s Program Requirements Document (PRD) Risk: “Risk of Performance Errors due to Fatigue Resulting from Sleep Loss, Circadian Desynchronization, Extended Wakefulness and Work Overload” and Integrated Research Plan (IRP) Gap Sleep5: “We need to identify environmental specifications and operational regimens for using light to prevent and mitigate health and performance decrements due to sleep, circadian, and neurobehavioral disruption, for flight, surface, and ground crews, during all phases of spaceflight operations.” Importantly, this work will lead to advances in new lighting systems for civilian applications in work places and homes.