VGSS: Reseach and Evidence

Published validation

VGSS's technical performance has been independently validated and reported in peer-reviewed literature. The 2026 technical report in Experimental Physiology is the definitive reference for VGSS's mechanical fidelity, demonstrating that simulated “vertical” ground reaction force profiles match theoretical predictions for the target gravity level across walking, running, and jumping tasks.

Full publication list:

• Swain, P., Swain, A., Santos, F., Hughes, L., Lindsay, K., Lomax, I., Bruce-Martin, C. & Caplan, N. (2026). Hypogravity simulation using the Variable Gravity Suspension System: A technical report. Experimental Physiology, 111(4), 1580–1596. doi:10.1113/EP092172
• Swain, P., Santos, F., Hughes, L., Gordon, D. & Caplan, N. (2025). Jumping on the moon as a potential exercise countermeasure. Experimental Physiology.
• Swain, P., Caplan, N. & Hughes, L. (2024). Blood flow restriction: The acute effects of body tilting and reduced gravity analogues on limb occlusion pressure. Experimental Physiology.

Operational history

ESA – E4D countermeasure evaluation: The ESA Space Medicine Team contracted the Aerospace Medicine and Rehabilitation Laboratory to use VGSS to evaluate exercises simulating those facilitated by the European Enhanced Exploration Exercise Device (E4D) under simulated microgravity conditions prior to parabolic flight testing and subsequent technology demonstration on the International Space Station. This was the first external licensed use of VGSS and demonstrated its role as a validated pre-flight analogue platform.

Fram2 – Personalised Tourniquet System for Spaceflight: Working with Western Clinical Engineering (Canada), VGSS was used to validate the Personalised Tourniquet System for Spaceflight (PTSS) under simulated microgravity conditions. Data generated using VGSS contributed to the spaceflight certification of the PTSS prior to its demonstration during the Fram2 polar orbit mission in 2025.

Research themes supported

VGSS is particularly well suited to research in the following areas, all of which align with ESA's Explore2040 priority themes:

• Crew health and performance – exercise countermeasures: Development, optimisation, and pre-flight validation of exercise devices and protocols for maintaining musculoskeletal and cardiovascular health during and after spaceflight. VGSS allows researchers to assess device performance under authentic gravitational loading, avoiding the challenges encountered with parabolic flight (e.g. duration of reduced gravity exposure).
• Crew health and performance – locomotion and mobility: Characterisation of human gait, running, jumping, and ballistic movement strategies at lunar and Martian gravity levels. Understanding movement patterns at reduced gravity is essential for habitat design, EVA suit development, and crew safety on planetary surfaces.
• Spaceflight hardware validation: Pre-flight evaluation of exercise hardware, medical devices, EVA suit components, and mobility aids under simulated partial gravity. VGSS provides conditions not replicable in parabolic flight (sustained duration) or neutral buoyancy (no true axial loading).
• Musculoskeletal physiology and rehabilitation: Investigation of muscle, bone, and cardiovascular responses to reduced gravitational loading. VGSS's integrated physiological monitoring suite – including NIRS, EMG, VO₂, ECG, and blood sampling – enables comprehensive physiological characterisation alongside biomechanical measurement.
• Blood flow restriction and novel exercise modalities: VGSS uniquely combines partial-gravity simulation with the ability to study blood flow restriction and resistance exercise modalities (cable-pull, flywheel), enabling investigation of countermeasure approaches relevant to both spaceflight and clinical rehabilitation.