At Work in the Destiny Laboratory of the International Space Station

NASA astronaut Mike Hopkins, Expedition 38 flight engineer, performs in-flight maintenance on combustion research hardware in the Destiny laboratory of the International Space Station in this image taken on Dec. 30, 2013. 

 Hopkins replaced a Multi-user Droplet Combustion Apparatus (MDCA) fuel reservoir inside the Combustion Integrated Rack (CIR). 

The Combustion Integrated Rack (CIR) includes an optics bench, combustion chamber, fuel and oxidizer control, and five different cameras for performing combustion experiments in microgravity. 

Image Credit: NASA