Microgreens, the young edible seedlings of vegetables and herbs, have gained significant attention for their dense nutritional content, rapid growth cycle, and minimal resource requirements, making them highly suitable for controlled environment agriculture. These characteristics position microgreens as a promising food source for space missions, where sustainability, efficiency, and compactness are critical. This book chapter explores the potential of microgreens in space food systems, emphasizing their adaptability to soil-less cultivation methods such as hydroponics and aeroponics, which are compatible with closed-loop life support systems. Key factors influencing their growth and quality, such as substrate selection, sowing density, and light spectrum, are discussed to optimize yields and nutritional value under extraterrestrial conditions. Advanced lighting technologies, particularly light-emitting diode (LED) based systems with specific spectral outputs, have demonstrated enhanced biosynthesis of essential vitamins, antioxidants, and phytochemicals in microgreens, contributing to astronaut health and resilience. Moreover, microgreens offer psychological benefits through their rapid growth and greenery in isolated space habitats. This chapter underscores the role of microgreens not only as a functional food but also as a multi-dimensional component of bioregenerative life support systems, contributing to food security, air purification, and crew well-being in long-duration space missions.