MicroAge mission: experimental design and hardware for a bespoke culture system supporting tissue-engineered skeletal muscle

Microgravity provides a unique model for accelerated skeletal muscle loss and potentially muscle ageing. During spaceflight, astronauts experience pronounced muscle atrophy, similar to age-related decline on Earth but over a much shorter timescale. Despite daily aerobic and resistance exercise on the International Space Station (ISS), countermeasures remain suboptimal, reflecting similar challenges seen in ageing populations. The MicroAge Mission used microgravity on the ISS to assess whether the molecular mechanisms behind reduced adaptive responses to contractile activity during ageing resemble those triggered by spaceflight. It also tested proof-of-concept genetic interventions, including Heat Shock Protein 10 (HSP10) overexpression, to mitigate muscle atrophy and functional loss. A tissue-engineering approach was used to fabricate human skeletal muscle constructs secured to 3D-printed scaffolds. These scaffolds incorporated microfluidic channels to interface with the flight hardware's fluid-handling system. The hardware, developed by Kayser Space Ltd, was designed to operate with the European Space Agency's (ESA) Kubik incubator on the ISS. This research addresses key methodological constraints in low Earth orbit (LEO) experimentation, outlining pre-flight protocol development, muscle construct biofabrication methods, and operational considerations. The findings provide a translational framework for future studies on musculoskeletal degeneration, with implications for therapies targeting both terrestrial ageing and astronaut musculoskeletal health.