Skip to page content Mission Information


Predicting Acute Cardiovascular and Ocular Changes Due to Changes in the Gravitational Vector and Effects of Countermeasures (80NSSC20K1521)
Principal Investigator
Research Area:
Cardiovascular physiology
Ocular physiological phenomena
Species Studied
Scientific Name: Homo sapiens Species: Human

Astronauts experience a chronic headward fluid shift when exposed to a weightless environment, causing a redistribution of blood and tissue fluid. This has unknown consequences to the overall behavior of the cardiovascular system and could potentially contribute to undesired changes in cardiovascular (CV) regulation, impaired cerebral venous flow, and the occurrence of Spaceflight-Associated Neuro-ocular Syndrome (SANS). SANS refers to the constellation of significant structural and functional neuro-ophthalmological findings in astronauts during both short- and long-duration exposure to microgravity. The etiology of SANS is currently unknown, but it is clearly related to the unique effects of microgravity on the body (e.g. loss of tissue weight, loss of hydrostatic gradients with the resulting fluid redistribution). Effective countermeasures and protocols that can reduce the headward fluid shifting in microgravity, such as lower body negative pressure (LBNP) or centrifugation, must be further investigated. However, at present, it is not possible to estimate the overall physiological response of a particular “dose” of either of these countermeasures.
This investigation seeks to characterize acute dose-response curves of cardiovascular and ocular variables due to changes in the gravitational vector with and without countermeasures and model these relationships using the following specific aims.
1) Generate dose-response relationships between CV and ocular parameters as a function of changes in the gravitational vector.
2) Develop a computational model to predict CV and ocular variables due to changes in the gravitational vector.
3) Identify, explore, and simulate the effects of countermeasures (i.e. LBNP, on CV and ocular parameters) using both experimental results and modeling techniques.

++ -- View more

Gravity, altered
Lower body negative pressure (LBNP)
Models, cardiovascular
Ocular physiological phenomena
++ -- View more

Data Information
Data Availability
Archiving in progress. Data is not yet available for this experiment.

Aorta cross-section area
Aortic impedance
Arterial blood saturation
Arterial compliance
Baroreflex sensitivity
++ -- View more

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

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
Proposal Source
2019 HERO 80JSC019N0001-FLAGSHIP & OMNIBUS: Human Research Program Crew Health. Appendix A&B