Skip to page content Mission Information


The Effects of Long-Term Exposure to Microgravity on Salivary Markers of Innate Immunity (Salivary_Markers)
Principal Investigator
Research Area:
Biomedical countermeasures
Species Studied
Scientific Name: Homo sapiens Species: Human

Immune system dysregulation and latent viral reactivation has been documented during and after space flight. This is of concern as NASA and other space agencies look ahead to multiple-year missions to the moon and Mars where the risk of an adverse health event due to dysregulated immunity will be considerably higher than during suborbital missions. Although the effects of space travel on both cellular and humoral immunity have been extensively studied, most of these have relied on samples collected before and after the mission. As such, there is a severe lack of data to determine how space travel affects immunity during the actual flight phase of the mission. Moreover, while changes in plasma cytokines and the phenotype and function of T-cells, neutrophils and monocytes have been relatively well studied, current knowledge on how space travel affects natural killer cells (NK)-cell function is limited.

NK-cells are a vital component of the immune system, performing both innate and adaptive functions that are critical to the recognition and destruction of malignant and virus-infected cells. Impaired NK-cell function due to space travel could adversely affect immune surveillance against cancer and viruses at a time when crewmembers are exposed to a stressful, high-radiation environment that promotes latent viral reactivation and possibly tumorigenesis. The primary aim of this study was to determine if NK-cell function is impaired during a six-month mission to the International Space Station (ISS). A secondary aim was to explore potential mechanisms for this anticipated reduction in NK-cell function, including changes in NK-cell phenotype differences between experienced and less-experienced crewmembers, and the involvement of plasma-associated factors.

++ -- View more

LaVoy EC, Bollard CM, Hanley PJ, O'Connor DP, Lowder TW, Bosch JA, and Simpson RJ. A single bout of dynamic exercise by healthy adults enhances the generation of monocyte-derived-dendritic cells. Cellular Immunology. 2015. February 25; 295(1):52-59. []

Spielmann G, Agha NH, Kunz H, Simpson RJ, Crucian BE, Mehta SK, Laughlin MS, and Campbell J. B cell homeostasis is maintained during long-duration spaceflight. Journal of Applied Physiology (1985). 2019. February 1; 126(2):469-476. [DOI]

Bigley AB, Agha NH, Baker FL, Spielmann G, Kunz HE, Mylabathula PL, Rooney BV, Laughlin MS, Mehta SK, Pierson DL, Crucian BE, and Simpson RJ. NK cell function is impaired during long-duration spaceflight. Journal of Applied Physiology (1985). 2019. April 1; 126(4):842-853. [DOI]

Spielmann G, Laughlin MS, Kunz H, Crucian BE, Quiriarte HD, Mehta SK, Pierson DL, and Simpson RJ. Latent viral reactivation is associated with changes in plasma antimicrobial protein concentrations during long-duration spaceflight. Acta Astronautica. 2018. May;146:111-6. [DOI]

Adaptation, physiological
Stress, psychological
Stress, psychological/immunology

Photo Gallery

Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
Data Sets+ Request data

Alpha amylase, saliva
Cortisol, Saliva
C-reactive protein, saliva
Dehydroepiandrosterone (DHEA), saliva
++ -- View more

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Expedition 37 09/10/2013 11/10/2013 61 days
Expedition 38 11/10/2013 03/10/2014 120 days
Expedition 39 03/10/2014 05/13/2014 64 days
Expedition 40 05/13/2014 09/10/2014 133 days
Expedition 41 09/10/2014 11/09/2014 29 days
Expedition 42 11/10/2014 03/11/2015 121 days
Expedition 43 03/11/2015 06/10/2015 91 days
Expedition 44 06/10/2015 09/11/2015 93 days
Expedition 45 09/11/2015 12/11/2015 91 days
Expedition 46 12/11/2015 03/02/2016 82 days
Expedition 47 03/02/2016 06/18/2016 108 days

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

The Human Research Roadmap is located at:

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

Additional Information
Other Key People
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Eric Gallagher
Institutional Support
National Aeronautics and Space Administration (NASA)
Alternate Experiment Name
Proposal Date
Proposal Source
Crew Health NNJ10ZSA003N