Biological system development for GraviSat: A new platform for studying photosynthesis and microalgae in space

摘要: Abstract Microalgae have great potential to be used as part of a regenerative life support system and facilitate in-situ resource utilization (ISRU) on long-duration human space missions. Little is currently known, however, about microalgal responses the environment over long (months) or even short (hours days) time scales. We describe here development biological subsystems for prototype “3U” (i.e., three conjoined 10-cm cubes) nanosatellite, called GraviSat, designed experimentally elucidate effects microgravity radiation microalgae other microorganisms. The GraviSat project comprises co-development handling-and-support technologies with implementation integrated measurement hardware photosynthetic efficiency physiological activity in (3–12 months) It supports sample replication fully autonomous that will grow analyze cultures 120 μL wells around circumference microfluidic polymer disc; launched while stasis, then grown orbit. disc spins at different rotational velocities generate range artificial gravity levels space, from multiples Earth gravity. Development comprised screening more than twenty strains various physical, metabolic biochemical attributes prolonged growth disc, well capacity reversible stasis. Hardware included necessary accurate precise measurements physical parameters by optical methods (pulse amplitude modulated fluorometry) electrochemical sensors (ion-sensitive microelectrodes). Nearly all were biocompatible nanosatellite materials; was rapidly inhibited (∼1 week) within sealed microwells did not include dissolved bicarbonate due CO 2 starvation. Additionally, oxygen production some resulted bubble formation wells, which interfered sensor measurements. Our research achieved periods (>10 without excess using two strains, Chlorella vulgaris UTEX 29 Dunaliella bardawil 30 861, lowering light intensities (2–10 μmol photons m −2  s −1 ) temperature (4–12 °C). Although experiments described performed develop platform, results this study should useful incorporation satellite payloads low-volume systems.