Exposure to weightlessness results in the removal of hydrostatic pressure gradients and a headward fluid shift. This has currently unknown consequences, but IT has been hypothesized to contribute to a…

Texas A&M Engineering Experiment Station has been awarded a $150,000 research grant effective January 1, 2025, through December 31, 2026, by a civilian federal agency operating through a Shared Services Center. This analog-based research effort investigates the physiological effects of lower body negative pressure (LBNP) as a potential countermeasure to spaceflight-associated neuro-ocular syndrome (SANS) and related cardiovascular complications experienced by astronauts during microgravity exposure. The research will utilize parabolic flight to generate acute dose-response curves measuring cardiovascular, autonomic, cephalad, and ocular responses across varying LBNP levels, addressing the fundamental gap between ground-based studies conducted under Earth conditions and the actual physiological responses occurring in true microgravity environments.

The contract is unencumbered by set-aside restrictions and represents a continuation of critical human spaceflight research aimed at understanding and mitigating the headward fluid shift and related vascular complications that occur when hydrostatic pressure gradients are removed during spaceflight. By conducting research in actual microgravity conditions rather than relying solely on Earth-based analogs, Texas A&M Engineering Experiment Station will provide essential data to inform the development and optimization of in-flight countermeasures designed to protect astronaut health during extended space missions. The award is consistent with the organization's extensive portfolio of federally-funded research spanning multiple agencies including NASA and reflects its established expertise in biomedical and aerospace research applications.

Exposure to weightlessness results in the removal of hydrostatic pressure gradients and a headward fluid shift. This has currently unknown consequences, but IT has been hypothesized to contribute to a series of neuro-ocular structural and functional changes occurring during spaceflight, collectively known as spaceflight associated neuro-ocular syndrome (sans). Additionally, recently demonstrated stagnant and retrograde blood flow and venous thrombosis in the left internal jugular vein (IJV) during spaceflight could also be associated with sustained headward fluid shift and removal of hydrostatic gradients. Thus, countermeasures focused on reversing the headward fluid shift, such as lower body negative pressure (lbnp), become particularly relevant. Previous studies on the ground (i.e., earth conditions, mostly in supine position or 6 head-down tilt) investigating the effects of lbnp have shown promising results. However, there are fundamental differences in physiological responses between earth and microgravity conditions (e.g., presence/absence of front-to-back, or GX, acceleration). Thus, ground results might not be directly extrapolated to true microgravity conditions. The objective of this analog-based research effort is to generate acute dose-response curves of a large set of cardiovascular, autonomic, cephalad, and ocular measures as a function of lbnp level during true microgravity conditions using parabolic flight.