failure of missions or instruments by reflying those missions or instruments where those data are deemed essential for scientific progress.
Finding 2: Strong ties with international programs are essential.
The current level of planned and proposed activity indicates that almost every space-faring nation is interested in establishing a foothold on the Moon. Although these international thrusts are tightly coupled to technology development and exploration interests, science will be a primary immediate beneficiary. NASA has the opportunity to provide leadership in this activity, an endeavor that will remain highly international in scope.
Recommendation 2: NASA should explicitly plan and carry out activities with the international community for scientific exploration of the Moon in a coordinated and cooperative manner. The committee endorses the concept of international activities as exemplified by the recent “Lunar Beijing Declaration” of the 8th ILEWG (International Lunar Exploration Working Group) International Conference on Exploration and Utilization of the Moon (see Appendix D).
Finding 3: Exploration of the South Pole-Aitken Basin remains a priority.
The answer to several high-priority science questions identified can be found within the South Pole-Aitken Basin, the oldest and deepest observed impact structure on the Moon and the largest in the solar system. Within it lie samples of the lower crust and possibly the lunar mantle, along with answers to questions on crater and basin formation, lateral and vertical compositional diversity, lunar chronology, and the timing of major impacts in the early solar system.
Missions to South Pole-Aitken Basin, beginning with robotic sample returns and continuing with robotic and human exploration, have the potential to be a cornerstone for lunar and solar system research. (A South Pole-Aitken Basin sample-return mission was listed as a high priority in the 2003 NRC decadal survey report New Frontiers in the Solar System: An Integrated Exploration Strategy.3)
Recommendation 3: NASA should develop plans and options to accomplish the scientific goals set out in the high-priority recommendation in the National Research Council’s New Frontiers in the Solar System: An Integrated Exploration Strategy’s (2003) through single or multiple missions that increase understanding of the South Pole-Aitken Basin and by extension all of the terrestrial planets in our solar system (including the timing and character of the late heavy bombardment).
Finding 4: Diversity of lunar samples is required for major advances.
Laboratory analyses of returned samples provide a unique perspective based on scale, precision, and flexibility of analysis and have permanence and ready accessibility. The lunar samples returned during the Apollo and Luna missions dramatically changed understanding of the character and evolution of the solar system. Scientists now understand, however, that these samples are not representative of the larger Moon and do not provide sufficient detail and breadth to address the fundamental science concepts outlined in Table 3.1 in this report.
Recommendation 4: Landing sites should be selected that can fill in the gaps in diversity of lunar samples. Mission plans for each human landing should include the collection and return of at least 100 kg of rocks from diverse locations within the landing region. For all missions, robotic and human, to improve the probability of finding new, ejecta-derived diversity among smaller rock fragments, every landed mission that will return to Earth should retrieve at least 1 kg of rock fragments 2 to 6 mm in diameter separated from bulk soil. Each mission should also return 100 to 200 grams of unfractionated regolith.