Understanding the ‘spaceflight treatment’ in plant space biology: Experimental practices, metadata workflows, and data re-analysis

The boundaries between targeted interventions, background factors, and confounders are concerns in all biological experimentation. Plant space biology takes these concerns to new territories not just geographically but also epistemically because of the operational constraints of collecting data in the multi-stressor spaceflight environment. In consequence, a central challenge in this field is the disentanglement of the various factors involved in the experiments and their tracing to biological effects on the plants. This paper characterizes the unique challenges of fundamental plant biology experiments and examines how secondary data analysis relying on metadata curation is providing novel ways to interpret, compare, and potentially integrate results obtained in these experiments. We propose an understanding of metadata workflows in comparative analyses of complex datasets as a form of post hoc experimental control that makes data tractable for interpretation in three ways: by providing a picture of the relevant intervening factors in experiments, refining the realm of comparison by keeping some conditions constant as background and others targets of analysis, and distinguishing between dependent and independent variables. More broadly, we maintain that this work can be regarded as an extension of experimental practice as it restructures the empirical resources on which researchers build analyses of past experiments and can contribute to the design of future ones.