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Small satellite technologies, particularly CubeSats, are enabling breakthrough research in space. Over the past 15 years, NASA Ames Research Center has developed and flown half a dozen biological CubeSats in low Earth orbit (LEO) to conduct space biology and astrobiology research investigating the effects of the space environment on microbiological organisms. These studies of the impacts of radiation and reduced gravity on cellular processes include dose-dependent interactions with antimicrobial drugs, measurements of gene expression and signaling, and assessment of radiation damage. BioSentinel, the newest addition to this series, will be the first deep space biological CubeSat, its heliocentric orbit extending far beyond the radiation-shielded environment of low Earth orbit. BioSentinel's 4U biosensing payload, the first living biology space experiment ever conducted beyond the Earth-Moon system, will use a microbial bioassay to assess repair of radiation-induced DNA damage in eukaryotic cells over a duration of 6-12 months. Part of a special collection of articles focused on BioSentinel and its science mission, this article describes the design, development, and testing of the biosensing payload's microfluidics and optical systems, highlighting improvements relative to previous CubeSat life-support and bioanalytical measurement technologies.

On Mars, we have yet to fully quantify atmospheric turbulent transport [Banfield, JASA (2016)]. The key required instrument is a wind sensor that can resolve horizontal and vertical winds, and the perturbations associated with turbulent eddies. On the surface, 10–20Hz sampling and a sensitivity of 5 cm/s are required (McBean, 1972). Viking, Pathfinder, Curiosity, and Insight used hot film or hot wire anemometers that can be confused by radiative heating and sample at approximately 1 Hz. Sonic anemometry is an alternative high speed, high accuracy approach which uses differences in the acoustic time of flight to determine flow speed. However, operation on Mars can be challenging due to the low acoustic source strength and high attenuation in the thin (6––11 mbar) CO2 atmosphere, as well as large temperature variations (−100°C to 20°C). In this paper, we describe an instrument that addresses these challenges: a 3 axis ultrasonic anemometer using custom low impedance, wide band transducers, low noise electronics, and an optimized mechanical structure. With an earlier prototype in wind tunnel tests in 6 mbar CO2, we demonstrated resolution better than 10 cm/s, and an accuracy of 3% at flow speeds up to 12 m/s. Data from an instrument flight to 128 000 feet on a stratospheric balloon will be presented, and progress towards a flight qualifiable instrument will be described.

This report describes the development of lab-on-a-chip device designed to measure changes in cellular ion gradients that are induced by changes in gravitational (g) forces. The bioCD presented here detects differential calcium ion concentrations outside of individual cells. The device includes sufficient replicates for statistical analysis of the gradients around multiple single cells and around control wells that are empty or include dead cells. In the data presented, the degree of the cellular response correlates with the magnitude of the g-force applied via rotation of the bioCD. The experiments recorded the longest continuous observation of a cellular response to hypergravity made to date, and they demonstrate the potential utility of this device for assaying the threshold of cells' g-force responses in spaceflight conditions.

We will present details and initial lab test results from an integrated bioanalytical microsystem designed to conduct the first biology experiments beyond low Earth orbit (LEO) since Apollo 17 (1972). The 14-kg, 12x24x37-cm BioSentinel spacecraft (Figure 1) assays radiation-responsive yeast in its science payload by measuring DNA double-strand breaks (DSBs) repaired via homologous recombination, a mechanism common to all eukaryotes including humans. S. cerevisiae (brewer's yeast) in 288 microwells are provided with nutrient and optically assayed for growth and metabolism via 3-color absorptimetry monthly during the 18-month mission. BioSentinel is one of several secondary payloads to be deployed by NASA's Exploration Mission 1 (EM-1) launch vehicle into approximately 0.95 AU heliocentric orbit in July 2018; it will communicate with Earth from up to 100 million km.

SporeSat – a lab-on-a-chip (LOC) centrifuge platform designed for integration as the payload of a small (5.5 kg), free-flying satellite – has been developed to determine the gravitational thresholds for calcium-ion channel activation of a single-cell spore from the fern Ceratopteris richardii. This fern is an important model system for gravity-directed plant-cell development during variable-gravity conditions attainable only in space flight. Calcium-ion channel activity is measured by photolithographically defined calcium ion–selective electrodes (ISEs) at opposite ends of each spore. Artificial gravity is created by rotating a disk-like platform that contains the spores in wells along with the calcium ISEs. Ground experiments reveal a maximum calcium concentration ratio at 2.2xg, between micro-ion-selective electrodes near the “top” and “bottom” ends of the spore, indicating an increasing calcium concentration at one “end” of the fern spore with respect to the other. Confocal micrographs of rhizoid formation confirm the light-induced germination. SporeSat is a spaceflight experiment that will take ~ 4 days; data will be telemetered to Earth over ~ 100 days.