Iss056e142871_alt (8/13/2018) .

iss056e142871_alt (8/13/2018) --- Astronaut Ricky Arnold prepares samples for the Barrios Protein Crystal Growth (Barrios PCG) experiment in the Maintenance Work Area (MWA) of the International Space Station (ISS). The Barrios PCG experiment defined an approach for optimizing protein crystallization conditions on orbit, eliminating the need to return samples to the ground during the optimization phase, which has the potential for saving substantial time and money on future PCG investigations in microgravity.