In this paper, we propose the use of a novel fixed-wing vertical take-off and landing (VTOL) aerobot. A mission profile to investigate the Isidis Planitia region of Mars is proposed based on the knowledge of the planet's geophysical characteristics, its atmosphere and terrain. The aerobot design is described from the aspects of vehicle selection, its propulsion system, power system, payload, thermal management, structure, mass budget, and control strategy and sensor suite. The aerobot proposed in this paper is believed to be a practical and realistic solution to the problem of investigating the Martian surface. A six-degree-of-freedom flight simulator has been created to support the aerobot design process by providing performance evaluations. The nonlinear dynamics is then linearized to a state-space formulation at a certain trimmed equilibrium point Basic autopilot modes are developed for the aerobot based on the linearized state-space model. The results of the simulation show the aerobot is stable and controllable.