The Mobile Lower Body Negative Pressure Gravity Suit for Long-Duration Spaceflight

Area of Science:

• Space Medicine
• Biomedical Engineering
• Human Physiology

Background:

• Long-duration spaceflight poses risks including Spaceflight Associated Neuro-ocular Syndrome, bone decalcification, and muscle atrophy.
• Lower Body Negative Pressure (LBNP) is a potential countermeasure, mitigating cephalad fluid shifts and providing ground-reaction forces (GRFs).
• Existing LBNP devices are bulky and restrict subject mobility.

Purpose of the Study:

• To introduce and evaluate a novel, mobile gravity suit as an improved countermeasure for spaceflight-induced physiological deconditioning.
• To test the hypothesis that the mobile gravity suit generates greater GRFs compared to a standard LBNP chamber.
• To assess the suit's effectiveness in simulating gravity-like loads for bone and muscle maintenance.

Main Methods:

• A comparative study was conducted using a novel mobile gravity suit and a standard LBNP chamber.
• Ground-reaction force (GRF) data were collected from subjects in a supine position using foot sole sensors and a weight scale.
• Measurements were taken at -40 mmHg, analyzing forces generated by both devices, including the novel force equation for the gravity suit.

Main Results:

• The mobile gravity suit generated a mean maximum bodyweight of 125 ± 22% at -40 mmHg (P < 0.02).
• The standard LBNP chamber generated 91 ± 24% of bodyweight.
• The mobile gravity suit produced higher GRFs by incorporating foot and waist cross-sectional areas (A_F + A_W) in its force generation equation, unlike the standard LBNP's waist-only calculation (A_W).

Conclusions:

• The novel mobile gravity suit significantly outperforms standard LBNP devices in generating GRFs, offering a more effective countermeasure for spaceflight-related physiological deconditioning.
• The suit's design, which includes foot loading (A_F × LBNP), enhances spinal loading and waist shear forces, better simulating terrestrial gravity.
• This mobile and flexible device represents a promising advancement for maintaining astronaut health during long-duration missions.