Regenerative processes for the revitalization of spacecraft atmospheres are required for extended duration space missions like the Space Station Freedom. A major atmosphere revitalization function is the recovery of oxygen from metabolic carbon dioxide by means of carbon dioxide reduction. The Sabatier carbon dioxide reduction technology is the baseline technology for the Space Station Freedom for this purpose.Life Systems has performed characterization and endurance testing of Sabatier reactor assemblies that has been used to design a prototype Sabatier reactor that complies with the performance requirements of the Space Station Freedom Carbon Dioxide Reduction Assembly. Information presented in the paper defines the testing that was used to design the prototype reactor and presents the successful test results that have been achieved using this reactor as part of an automated Sabatier based Carbon Reduction Assembly. Reactor performance as a function of temperature, pressure and reactant stoichiometry is defined.