Recently adopted “Space Policy Directive 1” emphasized on the development of innovative and sustainable program of space exploration. In particular, it stated the United States’s willingness to return to the Moon followed by the missions to Mars and other destinations: “...Lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. ......Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations” [1].