ARES would have traveled to Mars compactly folded into a protective aeroshell; upon entry in the thin atmosphere, the capsule would have deployed a parachute to decelerate, followed by ARES release at altitude.
Propulsion remained undetermined. The two main criteria used to evaluate the propulsion system were flight range and implementation risk. Possible propulsion technologies were electrical motors, internal combustion and rocket systems. The aircraft was intended to fly for about one hour.