Mars is a difficult place in which to fly. Its air pressure is equivalent to that of Earth at 100,000 feet (about .007 bar, or about 1%). To stay aloft, ARES will need to travel at speeds up to 450 miles per hour. ARES is very light, with most materials consisting of non-metallic composites. Engineering studies carried out at 102,000 feet above the Earth’s surface have demonstrated that ARES is a capable aircraft at even such low pressures. For navigation, a tail-mounted camera sends real-time images of the landscape ahead, while a downward-looking camera images objects less than a few centimeters across.