The use of the activated carbon produced from rice hulls to control NO,, emissions for future deep space missions has been demonstrated. The optimal carbonization temperature range was found to be between 600 and 750 degreesC. A burnoff of 61.8% was found at 700 degreesC in pyrolysis and 750 degreesC in activation. The BET surface area of the activated carbon from rice hulls was determined to be 172 m(2)/g when prepared at 700 degreesC. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 1.5 h when 10% oxygen was present and the ratio of the carbon weight to the flue gas flow rate (W/F) was 15.4 g.min/L. Reduction of the adsorbed NO to form N-2 could be effectively accomplished under anaerobic conditions at 550 T. The adsorption capacity of NO on the activated carbon was found to be 5.02 mg of NO/g of carbon. The loss of carbon mass was determined to be about 0.16% of the activated carbon per cycle of regeneration if the regeneration occurred when the NO in the flue gas after the carbon bed reached 4.8 ppm, the space maximum allowable concentration. The reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency.