A hybrid propulsion system presents many advantages for a potential Mars Ascent Vehicle including high specific impulse, restartability and predicted excellent low temperature survivability. This additional benefit of low temperature storage and operation could substantially reduce the power required to maintain the system while on Mars and therefore decrease the total landed system mass required for the system. A new wax-based hybrid fuel has been formulated to realize these low temperature benefits, while still preserving high performance (Isp). The freezing point of the oxidizer can be selected to match the capabilities of the fuel, in this case Mixed Oxides of Nitrogen has been selected. The main disadvantages of this system are associated with the relatively low technology readiness level of the selected hybrid propulsion system for operation on Mars. However, technology development efforts are currently underway to advance the hybrid propulsion system to a level where it could potentially compete with heritage propulsion systems. An internal study completed at JPL in 2015 identified the single stage to orbit hybrid MAV as the lowest gross liftoff mass case from a large range of potential propulsion systems. Updates to this design are presented here.