The Scientific Context for Exploration of the Moon Interim Report (2006) / Chapter Skim
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2 Scientific Themes, Goals, and Questions
2 Scientific Themes, Goals, and Questions
Pages 8-17
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From page 8... ...
The heavily cratered surface of the Moon testifies to the importance of impact events in the evolution of terrestrial planets and satellites and the exceptional ability of the lunar surface to record them all. Lunar bombardment history is intimately and uniquely intertwined with Earth's, where the role of early intense impacts and possible periodicity in large impact events in the recent past on the atmosphere, environment, and early life underpin our understanding of habitability.
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From page 9... ...
There are several outstanding issues that merit detailed further study in understanding the lunar flux curve and being able to use it to date other planetary surface features. Examples include the abundance of secondary impact craters and how they can be distinguished, potential latitudinal and hemispherical asymmetries in the number of formed impact craters, and the exact shape of the size-frequency distributions of solar system projectiles.
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From page 10... ...
The concept of a planetary magma ocean, though founded on lunar science, has become the one applied to the history of all the terrestrial planets. Though the concept of the lunar magma ocean continues to serve us well, geophysical, remote sensing, and sample analyses reveal a lunar crust that varies both laterally and vertically in composition, age, and mode of emplacement.
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From page 11... ...
In this context, the Moon provides unique information because it allows the study of cratering processes over several orders of magnitudes, from micrometeorite impacts on glassy lunar samples to the largest basin in the solar system, the South Pole-Aitken basin. The large number of lunar impact craters over a wide range in diameters provides the basis of statistically sound 11
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From page 12... ...
" Cratering is one of several such processes, affecting the lunar surface, the crust, and possibly even the mantle; each advance in understanding of cratering mechanics moves researchers closer to answering that key scientific question. Current hypotheses and assumptions about cratering processes underpin many of the hypotheses about the composition and evolution of the lunar crust, and thus the rest of the solar system.
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From page 13... ...
In summary, multiple opportunities will be present during implementation of the Vision for Space Exploration to constrain processes involved in regolith evolution and decipher ancient lunar environments from regolith samples. Theme 7: The Moon may provide important information about the early Earth and the origin of life.
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From page 14... ...
The potential sources are solar wind gas, volatile-rich comets, asteroids, and interplanetary dust particles, and even volatile material from giant molecular clouds through which the solar system periodically passes. The possible processes operating on these volatiles range from mass fractionation during transport, to retention from burial and chemical alteration processes, to losses from solar wind and galactic ultraviolet radiation and micrometeorites.
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From page 15... ...
Even so, a positive result by upcoming orbital remote sensing missions will not answer the most compelling scientific questions; these can only begin to be addressed by robotic in situ measurements. (A negative orbital result does not diminish the potential scientific value of the poles, but does complicate their further investigation if candidate landing sites are not identified.)
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From page 16... ...
Later, as rocket traffic and human activities perturb the lunar atmosphere from its native state, studies of the environmental effects of human and robotic activity would be highly illuminating, as an "active experiment" in planetary-scale atmospheric modification. Before extensive human and robotic activity alters the tenuous lunar environment, it is important to understand processes involved with the atmosphere (exosphere)
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From page 17... ...
Overall, in the near future, it is important to determine the utility of the Moon for astrophysics observations and as a platform for making observations of Earth and of solar-terrestrial processes.
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