The International Space Station (ISS) is the biggest multinational space program ever with 16 countries involved. Since November 2000 the station is permanently occupied with a crew of 3 astronauts. Till 2006 the station will be further assembled and the crew will be increased to 7 astronauts. To maintain a comfortable and safe environment under micro gravity conditions in a completely sealed space habitat advanced ventilation technology had to be developed to maintain air temperature, air humidity and air velocity as well as contaminant concentrations well below required levels. As resources are limited and upload costs are extremely high, one focus within the space station program is to close the oxygen loop, i.e. to recycle the exhaled CO2 laden air into fresh air. The paper gives a brief overview about the overall ventilation and contaminant removal system on the ISS and focuses on developed equipment and performance of closed loop system devices. Technology transfer examples of space hardware for terrestrial application within the HVAC community is given and market opportunities are shown.