Parallel emergence of cell culture capabilities in space and the development of a ground-based simulation of some microgravity conditions, has provided the folio of initial observations that spur the interest in the potential for applied research in microgravity.  The ground-based Rotating Wall Vessel is an analog culture system which provides a strategy for developing hypotheses and refining protocols for actual flight experiments.  To date, there are more than 350 publications on the use of microgravity analogs and microgravity itself in the investigation of mammalian, insect, plant, and microbial cells.

 biotechnology. Proximal tubule cells from the kidney are responsible for synthesis of an important hormone in red cell development, erythropoietin, and for synthesis of precursors to vitamin D.  The analog system demonstrated in vitro synthesis of native (not recombinant) hormone and vitamin D precursor by living cells.