A high-resolution digital holographic microscope for space flight

A common-path digital holographic microscope (DHM) was constructed for flight on the International Space Station (ISS), with modifications to permit the instrument to survive vibration, to meet the requirements of crew safety, and to operate within the ISS Life Sciences Glovebox (LSG). As a test of the instrument, a science experiment was conducted to examine phenotypic behavior and transcriptomics of the marine psychrophile <i>Colwellia psychrerythrea</i>. The cells were launched in cell-culture bags and grown onboard at +2&deg;C, and aliquots were manually transferred by the crew to imaging chambers. The crew manually evacuated bubbles from the bags and transfer syringes during the imaging. Parallel ground experiments allowed for evaluation of the effects of microgravity on cell motility phenotypes and preservation of cells for transcriptomic analysis. The instrument performed well after launch in the microgravity environment and the bacteria showed trackable motility. Future studies will allow for automated sample delivery without crew involvement and will fully analyze changes in gene expression.