Schmitt noted on the LunarListserv: "Having been deeply involved in this issue for many years, and having led several objective studies related to it, it is clear to me, and many other knowledgeable people, that returning to the Moon is the fastest and most cost effective path to Mars for the following reasons:"
1. We need generations of engineers to relearn how to operate in deep space at and for long durations on a location that is more accessible than a trajectory to Mars or on Mars itself.
2. We have no clear technology approach for landing large payloads (40MT+) on Mars. Developing entry, descent and landing (EDL) concepts and testing those concepts in the Earth's upper atmosphere will be a major program in and of itself with uncertain cost and duration.
3. Knowing whether 1/6th g triggers human re-adaptation from the adverse consequences of 0g is critical to the design and mass of both Mars transportation systems and Mars surface operations.
4. Many concepts that will be required for operations on Mars need testing in a real-world deep space environment before committing to using those concepts in Mars exploration, including autonomous crew operations during entry, decent, landing and real-time exploration without communications support from Earth.
5. We need a heavy lift launch infrastructure that can support the assembly of large interplanetary spacecraft in Earth orbit, and the requirements to return to the Moon support the development of that infrastructure.
6. We need to develop an interplanetary propulsion system that allows continuous acceleration and deceleration so the travel time to Mars can be cut significantly. That also constitutes a program of uncertain duration and cost.
7. Depending on future understanding of several unknowns already mentioned above, access to lunar-derived consumables after leaving Earth-orbit may be necessary to reduce the launch mass of an interplanetary spacecraft to a feasible amount.
8. We need to certify sample collection and protection protocols on the Moon with exposure to lunar dust and polar volatiles as surrogates for micro-organisms or the planetary protection lobby will make sample return from Mars impossible.
9. We need to use robotic drilling and definitive testing on Mars to penetrate what is probably the only potential biogenesis and evolutionary environment on Mars that has been stable for >3.8 billion years, namely, the cryosphere-hydrosphere interface below the surface.
10. Extremely strong scientific reasons for further lunar exploration exist as have been documented by a large fraction of the lunar and planetary research community at the NASA Advisory Council's 2007 Tempe Workshop and by the National Research Council's recent study.
11. Returning to the Moon has a far better chance of sustained political support than does a far, far more costly, start from scratch Mars program.
Absent sustained and increased budgetary support for the Vision for Space Exploration by the incoming Administration and Congress, any deep space initiative will be in doubt.
12. Finally, becoming a deep space-faring nation again constitutes a mult-generational endeavor, particularly if Mars is in the mix. Unfortunately, the government-run, politicized K-12 school system will not currently support such an endeavor. It has totally failed several generations of young people, not just in STEM subjects but in history, language and economics. This problem has to be solve first. The people requirements for a return to the Moon should help jump start that process, although it will take a much more grassroots effort to be successful.