This paper discusses approaches to Mars in-situ resource utilization (ISRU) using the reverse water gas shift (RWGS) reaction, which offers a potential means of producing oxygen on Mars at a significantly lower energy cost than the zirconia-electrolysis system. The RWGS also can be used as the first step in a process to produce either ethylene or methanol, both of which are storable fuels on Mars. The advantage of producing ethylene is that it minimizes the amount of hydrogen that needs to be transported to Mars to support in-situ propellant production. The advantage of producing methanol is that it minimizes the power requirement of the in-situ propellant production system. Highly promising preliminary experimental results of research on Mars ISRU systems using the RWGS are reported. Scalings are provided showing power and mass estimates for Mars ISRU systems across the span of potential mission applications. Mission analysis of both the Mars Sample Return and robotic Mars Ballistic Hopper missions are presented, showing strong advantages for those systems utilizing the RWGS. It is concluded that the RWGS system, both by itself or in combination with either ethylene or methanol formation reactors offers great potential for enhancing future Mars exploration and should be researched further.