LEIA: NASA’s first biological mission on the lunar surface since 1972

The Lunar Explorer Instrument for space biology Applications (LEIA) mission was awarded in 2022 by NASA. LEIA will be delivered to the lunar surface no earlier than 2027 on a commercial lunar lander. It aims to investigate the effects of the lunar surface environment on biological organisms. Particularly, LEIA will study the effects on different DNA damage and stress response mechanisms, as well as on synthetic bioproduction of antioxidants in the budding yeast Saccharomyces cerevisiae. To achieve these aims, LEIA consists of a science suite of three instruments: a microfluidic-based system (BioSensor) with microbial growth support capabilities, a charged particle detector (LET spectrometer), and a mini fast neutron detector (mini-FND). The BioSensor instrument has high heritage from NASA's BioSentinel CubeSat mission, which launched to a heliocentric orbit onboard the Artemis I rocket in late 2022 (currently at 60 million kms from the Earth). An identical BioSensor payload successfully performed biological experiments on the International Space Station (ISS) in 2021–2022. The BioSensor instrument contains a complex fluidic system that delivers nutrients to desiccated yeast cells in fluidic cards. Growth and metabolic activity are monitored via optical absorbance measurements, thus allowing for the detection of changes caused by cellular or DNA damage on the lunar surface. In addition, it allows to measure and detect the effects on the bioproduction of dietary antioxidants. The LET spectrometer and mini-FND instruments will quantify and characterize the lunar surface radiation environment. Thus, LEIA will support the development of potential countermeasures for future human missions to the Moon. In addition to using high-heritage instrumentation, many lessons learned from BioSentinel have been implemented in the design and development of LEIA.