Important information can be gained through simple experiments in which organisms are taken to space, chemically fixed (or stabilized), and then returned for post-flight processing. The BRIC-PDFU is designed to accomplish this using a minimal amount (typically less than one hour) of astronaut crew time. Biological specimens are placed onto (or into) 60 mm Petri dishes containing agar-solidified media, although alternative approaches will be considered. Each Petri dish is then placed inside its own individually sealed PDFU. The PDFUs are assembled and loaded with up to 17mL of either one or two fluids, such as a nutrient solution and/or a chemical fixative, in a reservoir compartment as specified by the selected investigators. Six PDFUs, or five PDFUs plus one temperature data logger depending on the investigator’s requirements, are then loaded into each BRIC canister. Along with the BRIC-PDFUs, actuator equipment is flown that the crew uses to actuate the hardware. Crew members perform up to two in-flight operations per PDFU to expose the biology to liquid treatments (determined by the selected investigators) and/or chemical fixatives (e.g., glutaraldehyde, RNAlater, formaldehyde) on-orbit prior to return.
A diverse range of investigations can be undertaken, including, but not limited to, plant seedlings (e.g., Arabidopsis thaliana and Medicago truncatula), callus cultures, Caenorhabditis elegans, microbes, and others. The PDFUs remain contained within the BRIC canisters during all phases of flight operations. In a typical usage scenario, the BRIC-PDFUs can be stowed at a predetermined temperature (for example +4°C) for ascent and transfer to the ISS, activated on orbit by warming to ambient or placement in an incubator, actuated by the crew, thereby preserving specimens for return, and then transferred to cold stowage such as the Minus-Eighty Degree Laboratory Freezer (MELFI) or other ambient stowage based on experiment objectives. In the event of a launch scrub the entire assembly can be replaced with an identical back-up unit in order to maintain freshly loaded specimens.