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Fatigue Countermeasures Laboratory

Mission Statement

The mission of the Fatigue Countermeasures Laboratory is to provide a better understanding of sleep and circadian rhythm-related issues as they affect human performance and safety, and to develop countermeasures to improve safety, alertness, performance, and aid in overall mission success.

Four of the five STS-51 crew members were photographed during one of their sleep periods on Discovery's middeck
STS051-20-037 (12-22 Sept 1993) — Four of the five astronaut crew members were photographed during one of their sleep periods on the Space Shuttle Discovery’s mid-deck. At bottom center, astronaut Frank L. Culbertson, Jr., mission commander, is barely visible, with most of his body zipped securely in the sleep restraint. Others, left to right, are astronauts Daniel W. Bursch and Carl E. Walz, mission specialists, and William F. Readdy, pilot. The photograph was taken by astronaut James H. Newman, mission specialist.
Credit- NASA

Lab Overview

Alertness and performance are negatively impacted by circadian misalignment (being out of sync with one’s internal body clock), acute sleep loss (insufficient sleep over a short period of time), chronic sleep loss (insufficient sleep over a long period of time), and sleep inertia (grogginess following sleep).

The Fatigue Countermeasures Laboratory at NASA Ames Research Center studies the relationship between these factors and assesses countermeasures to improve safety, alertness, performance, and aid in the overall success of a mission’s goal. The primary populations of interest are aviation pilots and astronauts; however, the Fatigue Countermeasures Laboratory lends its expertise to diverse populations.

NASA researcher Dr. Erin Flynn-Evans, lead of NASA's Fatigue Countermeasures Group, prepares a research subject for a fatigue study.
NASA researcher Dr. Erin Flynn-Evans, lead of NASA’s Fatigue Countermeasures Group, prepares a research subject for a fatigue study.
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Recruiting Participants for Studies

If you are interested in participating in a NASA Fatigue research study, or would like to be notified when we publish the results of studies, please click on the links below:

– General Population
– Pilots

Laboratory Research

Spaceflight Countermeasures

Spaceflight missions often involve operational constraints that require astronauts to work during the biological night and to sleep during the biological day. This circadian misalignment can cause reductions in alertness and performance and sleep disruption. There are countermeasures, such as caffeine and hypnotics that can be used to mitigate some of these challenges, but they come with consequences that make them unsuitable for many situations. Our laboratory is testing novel, non-pharmacological countermeasures that can be used during spaceflight missions.

Sleep Inertia Studies

Sleep inertia refers to the grogginess and impaired performance experienced immediately after waking. This transitory period can have significant consequences for occupations in which optimal readiness is required immediately after waking (e.g., aviation, spaceflight, emergency services, and health care). We are investigating countermeasures that can be applied after waking to restore alertness and performance as quickly as possible. Our studies have identified blue-enriched light as a possible reactive countermeasure both in the laboratory and in a translational study conducted in an at-home setting. We are continuing to explore the effectiveness of light under different conditions, as well as other interventions to mitigate sleep inertia.

Changes in Eye Movements During Sleep Loss and Circadian Misalignment – COBRA

In recent years, our studies, in collaboration with the Visuomotor Control Laboratory, investigated the effects of sleep loss on cognitive functioning and the visual motor system to support the development of NASA’s Comprehensive Oculomotor Behavioral Response Assessment (COBRA). COBRA is a behavioral oculomotor tracking task that assesses various oculometrics (e.g., pursuit and saccade behavior, pupillometry). More information on COBRA can be found here: >> (link to COBRA/Vision Group). <<

Chronic Sleep Restrictions

Chronic Sleep Restriction (CSR) occurs when an individual obtains less sleep than they need over several consecutive days. CSR results in cognitive impairment, including reduced alertness, attention, memory, executive functioning, and a contributing factor to many chronic health issues (e.g., heart disease, obesity, diabetes, anxiety/depression). In occupations that require optimal alertness and attention, such as aviation, spaceflight, and military operations, it is important to understand the consequences of CSR so that we can predict and mitigate those consequences through various techniques and countermeasures. In our CSR studies, participants followed a strict 5-hour time in bed schedule every night for one week concluding with a 13-hour day-time lab visit. Participants then completed a 9-hour time in bed schedule every night for one week concluding with a second 13-hour day-time lab visit.

Acute Sleep Deprivation

Acute sleep loss is a form of sleep deprivation that occurs when an individual experiences loss of sleep over a short period (often over 24-48 hours). Like CSR, acute sleep loss can result in cognitive impairment and health issues. Many shiftwork occupations are often susceptible to periods of acute sleep loss. Our lab seeks to better understand the effects of acute sleep loss to develop countermeasures and techniques to mitigate such effects. In our acute sleep loss studies, participants remain awake in the lab for a 24-hour period during which they undergo a constant routine protocol (e.g., controlled temperature and lighting, limited physical activity, small isocaloric meals) to measure their circadian rhythm.

Autonomous Vehicles

Human error has been implicated as a causal factor in a large proportion of road accidents. Automated driving systems purport to mitigate this risk, but self-driving systems that allow a driver to entirely disengage from the driving task also require the driver to monitor the environment and take control when necessary. Given that sleep loss impairs monitoring performance and there is a high prevalence of sleep deficiency in modern society, we hypothesized that supervising a self-driving vehicle would unmask latent sleepiness compared to manually controlled driving among individuals following their typical sleep schedules. We found that participants felt sleepier, had more involuntary transitions to sleep, had slower reaction times and more attentional failures, and showed substantial modifications in brain synchronization during and following an autonomous drive compared to a manually controlled drive. Our findings suggest that the introduction of partial self-driving capabilities in vehicles has thepotential to paradoxically increase accident risk.

Aviation Research

Air traffic controllers have demanding, safety-critical jobs that require complex cognitive capabilities, including tracking, switching attention, communication, and calculating, among others. Fatigue, in the form of sleep loss and circadian misalignment, has the potential to introduce lapses of attention and increase errors. In order to better understand the causes and consequences of fatigue among air traffic controllers, Dr. Flynn-Evans was appointed to an FAA panel to investigate these issues. The report identified 58 opportunities for improvement that were summarized in a report published in 2024. The lab continues to support air traffic operations through a combination of research, technology development, and fatigue risk management support.

Long-Haul Flight Operations

Long-haul flight operations involve a number of fatigue-related challenges, including circadian disruption from crossing multiple time zones, long flights, different layover patterns, and the effects of jet lag on alertness, performance, sleep, and recovery. Understanding how time zone transitions, sleep opportunities during in-flight rest, and layover influence alertness and cognitive performance is essential for developing effective fatigue mitigation strategies. Our lab has conducted several studies examining flight crew alertness and sleep during long-haul flights, including inflight controlled rest, layover start timing and duration. Currently, we are investigating the use of the Large Language Model to analyze pilot narrative reports in order to identify factors that contribute to fatigue in short- and long-haul aviation.

Short-Haul Flight Operations

Short-haul flight operations (flight segments <6 hours) face a unique set of fatigue challenges such as early starts, late finishes, and overnight flying (“redeyes”), as well as high workload due to multiple take-offs and landings within a duty period. Understanding these factors is critical for developing countermeasures that can be implemented within the constraints of these operations. Our lab has conducted a number of studies to better understand the impacts of schedules, workload, and light interventions. We also conducted a comprehensive in-flight study of circadian disrupted schedules (i.e., redeyes and “swaps”) informed by focus groups of short-haul pilots to assess the impact on sleep, sleepiness, fatigue, workload, and performance.

Spaceflight/Analog Habitat Research

Spaceflight Standard Measures

The Spaceflight Standard Measures project is a large, cross-cutting project that involves the collection of a set of core measurements to inform many human spaceflight risks. Sleep is measured via wrist-worn accelerometer devices (actigraphy) and questionnaires. This study allows for regular surveillance of sleep to understand the factors that influence crewmembers’ ability to obtain adequate quality and quantity of sleep in space.

Volatiles Investigating Polar Exploration Rover (VIPER)

VIPER is a robotic exploration mission that will require teams of human operators to control a lunar rover remotely from an Earth-based mission control center. Due to the lack of prior research on sustained real-time reactive mission control operations, we evaluated sleepiness, performance, and workload during a simulated operation to better inform scheduling and staffing requirements in preparation for the mission. Assessing individuals trained to operate the simulation, our findings indicated that participants’ performance worsened over time when operating in the middle of the night with greater errors made in the early hours of the morning. We continue to work with the VIPER team to provide recommendations for scheduling, fatigue risk management, and countermeasures, including modifications to lighting in the mission control center.

Crew Health and Performance Exploration Analog (CHAPEA)

Crew Health and Performance Exploration Analog (CHAPEA) is a research analog study where 4-member crews simulate year-long studies on Mars. We work with the CHAPEA science team to monitor sleep throughout the mission.

Human Exploration Research Analog (HERA)

Human Exploration Research Analog (HERA) is a research analog environment where 4-member crews simulate a variety of mission scenarios. We have conducted studies in the HERA habitat to evaluate the impact of chronic sleep restriction on crew alertness and performance. We have also evaluated the validity and reliability of biomathematical performance models and lighting countermeasures in this operational setting.

NASA PVT+ App

The NASA PVT+ App is a validated iOS mobile application developed for use in field settings. The NASA PVT+ app includes a version of the psychomotor vigilance task (PVT) based on the PVT-192. The app also includes a number of questionnaires and surveys in order to capture sleep, alertness, and operational outcomes in research studies. There are three, free publicly available versions of the app in the Apple App Store:  Simple PVT (just the PVT), Basic Study (single or multiday pre-set framework including sleep logs, PVT and sleepiness questionnaires), and Aviation Study (multiday pre-set framework for collecting aviation data).

NASA PVT+ Downloads

NASA PVT+ User Guide/Manual

Feb 27, 2026

PDF (1.62 MB)

NASA PVT+ Warnings and Notices

Feb 27, 2026

PDF (88.46 KB)

NASA PVT+ FAQs

Feb 27, 2026

PDF (95.08 KB)

Lab Personnel

Lab Director

Erin Flynn-Evans, Ph.D., MPH

Lab Members

Lucia Arsintescu

Nick Bathurst

Zachary Glaros

Kevin Gregory

Rachel Jansen, Ph.D.

Sean Pradhan, Ph.D.

Student Researchers

Ava Dixon- Ava joined the Fatigue Countermeasures Laboratory in 2024 as a student research collaborator through the San Jose State Research Foundation. She earned her MA in Research and Experimental Psychology from San Jose State University in the Fall of 2025. Her research focuses on neuropsychology, cognitive performance factors, and computerized assessment tools. Currently, she supports the lab by facilitating polysomnography scoring. She hopes to aid in refining cognitive and physiological measurements to enhance performance in space flight.

Angill Oliva – Angill joined the lab as a summer intern in 2024 and completed her M.A. in Research and Experimental Psychology at San José State University in 2025. Her thesis examined the initial user experience of a gamified mental health app, integrating human-centered design with behavioral science. She is particularly interested in wearable technologies that capture physiological markers of circadian rhythms, especially under extreme conditions such as sleep deprivation or spaceflight. She is also interested in exploring how biometric signals from wearables can serve as indicators of alertness and performance.

Michelle Tripp

Lindsey Wade

Summer Internship Program

The Fatigue Countermeasures Laboratory provides a unique opportunity for undergraduate and graduate students to engage in a variety of research projects. These summer internships last 10-12 weeks beginning in June and ending in August. No prior experience is necessary; however, the best candidates will be open to new experiences and learning new things, able to work independently and with a team, punctual, and reliable.

If you are interested in an internship with the Fatigue Countermeasures Laboratory, please use the online application form below. * NOTE- This online application is administered by San Jose State University (San Jose State University Privacy Policy).

> Summer Internship Online Application Form