APPENDIX 3a

Scientific Questions in Lunar Exploration*

Major questions in the exploration of the Moon fall chiefly in three categories of basic problems:

1. structure and processes of the lunar interior,
2. the composition and structure of the surface of the Moon and the processes modifying the surface, and
3. the history or evolutionary sequence of events by which the Moon has arrived at its present configuration.

The major questions are as follows:

Structure and Processes of the Lunar Interior

1. Is the internal structure of the Moon radially symmetrical like the Earth, and if so, is it differentiated? Specifically, does it have a core and does it have a crust?
2. What is the geometric shape of the Moon? How does the shape depart from fluid equilibrium? Is there a fundamental difference in morphology and history between the sub-Earth and averted faces of the Moon?
3. What is the present internal energy regime of the Moon? Specifically, what is the present heat flow at the surface and what are the sources of this heat? Is the Moon seismically active and is there active volcanism? Does the Moon have an internally produced magnetic field?

Composition, Structure, and Processes of the Lunar Surface

1. What is the average composition of the rocks at the surface of the Moon and how does the composition vary from place to place? Are volcanic rocks present on the surface of the Moon?
2. What are the principal processes responsible for the present relief of the lunar surface?
3. What is the present tectonic pattern on the Moon and distribution of tectonic activity?
4. What are the dominant processes of erosion, transport, and deposition of material on the lunar surface?
5. What volatile substances are present on or near the surface of the Moon or in a transitory lunar atmosphere?
6. Is there evidence of organic or proto-organic materials on or near the lunar surface? Are living organisms present beneath the surface?

History of the Moon

1. What is the age of the Moon? What is the range of age of the stratigraphic units on the lunar surface and what is the age of the oldest exposed material? Is a primordial surface exposed?
2. What is the history of dynamical interaction between the Earth and the Moon?
3. What is the thermal history of the Moon? What has been the distribution of tectonic and possible volcanic activity in time?
4. What has been the flux of solid objects striking the lunar surface in the past and how has it varied with time?
5. What has been the flux of cosmic radiation and high-energy solar radiation over the history of the Moon?
6. What past magnetic fields may be recorded in the rocks at the Moon's surface?