Task Lighting Protocols for Exploration - HERA Campaign
Last Published:  07/29/22 01:33:24 PM (Central)
Short Title: Exploration Lighting Protocols
Responsible HRP Element: Human Factors and Behavioral Performance
Collaborating Org(s):
Funding Status: Active - Currently funded and in progress
Procurement Mechanism(s):

The overall goal of this project is to study how a programmable solid state lighting system would be used operationally to improve sleep, enhance alertness and performance, maintain optimal circadian entrainment, and readapt circadian phase if the circadian misalignment occurs, in a high fidelity simulation of the International Space Station (ISS) lighting environment, such as the Human Exploration Research Analog (HERA).  The HERA has been fitted with programmable LED lighting that is representative of the new solid state light assemblies (SSLAs) to be installed on the ISS.  The new SSLAs incorporate three pre-determined settings to address different operational needs: 1) white light for general vision; 2) blue-enriched high intensity white light to enhance alertness and circadian adaptation; 3) blue-depleted low intensity white light to minimize alertness prior to sleep.  A Dynamic Lighting Schedule (DLS) has been developed to determine when each of these three settings will be used to optimize lighting to improve alertness and performance, reset circadian rhythms and enhance sleep, while maintaining vision.  This project will apply the DLS in the HERA as the next step in examining the feasibility and efficacy of the SSLA system, and to provide the testing necessary to finalize the operational procedures for in-flight testing of the new lights aboard ISS.

The specific aims of this study are:

In a series of 30-day 2016 HERA Campaign missions, conduct randomized crossover within-subject clinical trials to test the hypotheses that deployment of the DLS, as compared to deployment of a standard, static lighting schedule, and while also maintaining acceptable visual performance and color discrimination for operational tasks, will:

i) significantly improve polysomnographic and subjective measures of sleep latency, sleep quality and sleep efficiency;

ii) significantly improve cognitive performance, subjective alertness and mood, and objective EEG correlates of alertness (suppression of EEG-derived delta-theta activity [0.5-5.5 Hz]) and enhancement of EEG-derived high-alpha activity [10.5-12 Hz]);

iii) significantly increase the rate of circadian adaptation, as measured using the circadian rhythm of melatonin and its metabolites before and after the shift.

The results of this investigation will yield knowledge needed for implementing a light countermeasure in the operational environment (specifically, ISS) as well as laying the ground work for testing the effectiveness, feasibility and acceptability of alternative protocols (e.g., pulsing) for Exploration vehicles. 
A supplemental aim was added to
examine Shuttle-period actigraphy data to determine if a relationship exists between reduced sleep quantity and CO2 levels between 3 mmHg and 2 mmHg CO2.