Engineering topics
Neal, Clive
Publications and source records attributed to Neal, Clive.
Cooling Rates of Lunar Volcanic Glass Beads
It is widely accepted that the Apollo 15 green and Apollo 17 orange glass beads are of volcanic origin. The diffusion profiles of volatiles in these glass beads are believed to be due to degassing during eruption (Saal et al., 2008). The degree of degassing depends on the initial temperature and cooling rate. Therefore, the estimations of volatiles in parental magmas of lunar pyroclastic deposits depend on melt cooling rates. Furthermore, lunar glass beads may have cooled in volcanic environments on the moon. Therefore, the cooling rates may be used to assess the atmospheric condition in an early moon, when volcanic activities were common. The cooling rates of glasses can be inferred from direct heat capacity measurements on the glasses themselves (Wilding et al., 1995, 1996a,b). This method does not require knowledge of glass cooling environments and has been applied to calculate the cooling rates of natural silicate glasses formed in different terrestrial environments. We have carried out heat capacity measurements on hand-picked lunar glass beads using a Netzsch DSC 404C Pegasus differential scanning calorimeter at University of Munich. Our preliminary results suggest that the cooling rate of Apollo 17 orange glass beads may be ~12 K/min, based on the correlation between temperature of the heat capacity curve peak in the glass transition range and glass cooling rate. The results imply that the parental magmas of lunar pyroclastic deposits may have contained more water initially than the early estimations (Saal et al., 2008), which used higher cooling rates, 60-180 K/min in the modeling. Furthermore, lunar volcanic glass beads could have been cooled in a hot gaseous medium released from volcanic eruptions, not during free flight. Therefore, our results may shed light on atmospheric condition in an early moon.
The Global Exploration Roadmap: Opportunities for Lunar Science
The Global Exploration Roadmap (GER) has been developed by the International Space Exploration Coordination Group (ISECG comprised of 14 space agencies) to define various pathways to getting humans beyond low Earth orbit and eventually to Mars. Such pathways include visiting asteroids or the Moon before going on to Mars. This document has been written at a very high level and many details are still to be determined. However, a number of important papers regarding international space exploration can form a basis for this document.This poster will focus on developing the Lunar Vicinity scenario by adding detail via mapping a number of recent reportsdocuments into the GER. The documents highlighted here are in no way meant to be all encompassing and other documents can and should be added, (e.g., the JAXA Space Exploration Roadmap). This exercise is intended to demonstrate that existing documents can be mapped into the GER despite the major differences in granularity, and that this mapping is a way to promote broader national and international buy-in to the Lunar Vicinity scenario.The documents used here are: the Committee on Space Research (COSPAR) Panel on Exploration report on developing a global space exploration program, the Strategic Knowledge Gaps (SKGs) report from the Lunar Exploration Analysis Group (LEAG), the Lunar Exploration Roadmap developed by LEAG, the National Research Council report Scientific Context for the Exploration of the Moon (SCEM), and two journal articles, the scientific rationale for resuming lunar surface exploration, and the astrobiological benefits of human space exploration.In addition, the ISECG is in the process of developing a Science White Paper (SWP) to accompany the next edition of the GER, due in late 2016. The SWP will be an important tool to communicate science which will be able to be accomplished at human exploration destinations to policymakers. This abstract will discuss the process of developing this SWP and ways in which the global science community can become engaged in its development.
Water in the Oldest Lunar Rocks: Moon is "Wetter" than Previously Thought
No abstract available