Liquid metals for the booming of space exploration

<h2>Summary</h2> Liquid metals (LMs) are becoming central to tackling many extreme technical bottlenecks facing space exploration. The unique microgravity and vacuum environment of space also poses big challenges and is an unprecedented laboratory to explore unknown sciences. This perspective presents an overview of the fundamentals and practical issues and envisions future opportunities for LMs in space exploration, focusing on their roles in energy systems, deep space propulsion, thermal management, flexible electronics, reconfigurable machines, additive manufacturing, life support systems, and space optics, among others. Beyond practical engineering, we further outline the potential to exploit the space environment as a unique and indispensable platform to probe LM interfacial physics and chemistry free from gravitational constraints. Prospects for disclosing microgravity-related self-organization phenomena and thus enriching fundamental breakthroughs are interpreted. Collectively, these insights establish LMs as not only generalist materials but also transformative enablers for the booming of future space science and technology.