Methane Fuel Carbon dioxide from atmosphere Synthesize return-journey fuel on Mars O 2H O + CO -> CH + 2O O C O C 2 2 4 2 O O H C H O O H H O Water from below ground H O O H H H

Methane Fuel Carbon dioxide from atmosphere Synthesize return-journey fuel on Mars O 2H O + CO -> CH + 2O O C O C 2 2 4 2 O O H C H O O H H O Water from below ground H O O H H H