MAV fuel tank – Collects CO₂ (from Mars atmosphere) and converts hydrogen and CO₂ (by [Sabatier] chemical reaction) to fuel for MAV ascent to the spaceship, Hermes. MAV takes 20 hours to fill 10 litre fuel tank with CO₂ – ½ litre per hour. For every 1kg of hydrogen it makes 13 kgs of fuel.