Carbon Dioxide Reprocessing Subsystem for Loop Closure as part of the Regenerative Life Support System ACLS



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46th International Conference on Environmental Systems


In view of future manned space exploration Life Support Systems are mandatory for human survival in space. Late in 2017, a new regenerative Life Support System, named Advanced Closed Loop System (ACLS), shall be installed on board the International Space Station as Technology Demonstrator for future space missions. The important unit to close the regenerative process is the Carbon Dioxide Reprocessing Subsystem (CRA) processing H2 and CO2 to Water Vapour and CH4 by the means of the Sabatier Reaction. The supply of H2 is provided by the ACLS Subsystems OGA (Oxygen Generation Subsystem) and CO2 by the CCA (Carbon Dioxide Concentration Subsystem). The core of the CRA is a two-staged Sabatier Reactor and a water recovery unit downstream the Reactors to separate the water. The special design of the Reactor Assembly has been developed and improved since years assuring a high conversion rate of H2. The Reactor Assembly comprises the Reactor containing a certain catalyst and the thermal insulation to reduce the heat loss to a minimum. The first stage of the Reactor operates adiabatic at very high temperature to ensure a high reaction rate. The second stage, operating at a lower temperature compared to the first stage, is air cooled to maintain isothermal conditions thus increasing the conversion rate. This paper describes on the one hand in detail the development and improvements of the Sabatier Reactor Assembly over the years and presents the current hardware built status. On the other hand it describes the Sabatier process with test results gained during the stand-alone Subsystem Testing and the closed-loop operation ACLS System Testing on Engineering Model Level.


Airbus Defence and Space GmbH
European Space Agency
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
Vienna, Austria
Fabian Kappmaier, Airbus DS GmbH – Space Systems, Germany
Carsten Matthias, Airbus DS GmbH – Space Systems, Germany
Johannes Witt, ESA-ESTEC, The Netherlands
The 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.


Advanced Closed Loop System ACLS, Regenerative Life Support System, Carbon Dioxide Reprocessing Subsystem CRA, Sabatier Reaction, International Space Station ISS