Provided is a testbed for conducting an experiment on a substance in a cryogenic liquid state in a microgravity environment. The testbed includes a frame with rectangular nominal dimensions, and a source section including a supply of the substance to be evaluated in the cryogenic liquid state. An experiment section includes an experiment vessel in fluid communication with the storage section to receive the substance from the storage section and condense the substance into the cryogenic liquid state. A sensor is adapted to sense a property of the substance in the cryogenic liquid state in the experiment vessel as part of the experiment. A bus section includes a controller configured to control delivery of the substance from the storage section to the experiment vessel, and receive property data indicative of the property sensed by the sensor for subsequent evaluation on Earth.