ISS037-E-021985 (28 Oct. 2013) --- In the International Space Station?s Tranquility node, NASA astronaut Michael Hopkins (right) and European Space Agency astronaut Luca Parmitano, both Expedition 37 flight engineers, perform routine in-flight maintenance within the Carbon Dioxide Removal Assembly. This device removes carbon dioxide from the station?s atmosphere and is part of the station?s Environmental Control and Life Support System that provides clean water and air to the crew.