We propose to investigate five Hayabusa grains by synchrotron x-ray techniques, electron microscopy, nano-FTIR, Raman spectroscopy, and SIMS. It is necessary to characterize the mineralogy/petrology of many more Hayabusa grains in order to understand the origin and processing of surface regolith on asteroid Itokawa.
Using the range of techniques that our collaboration has experience with, we will characterize the mineralogy/petrology of five Hayabusa grains. We seek to better understand the range of O isotopic composition of Itokawa regolith and search for foreign impactor material which would be distinguished by its non-L/LL O isotopic composition. Using TEM, we will quantify the abundance and investigate the chemical makeup of nanophase Fe particles which are responsible for the space-weathered S-type spectrum of Itokawa. In Al-rich, Mg-poor phases, such as plagioclase, we will measure the 26Al-26Mg system in order to better constrain the former presence of radioactive 26Al (likely responsible for the ∼600◦–700◦ C thermal metamorphism of Itokawa) in several Hayabusa grains. We will apply Raman, nano-FTIR, EPMA, TEM, and synchrotron techniques to our allocated samples and direct further analyses based on what we find.
Our group has developed a reversible sample preparation procedure that facilitates the most economical use of precious samples. We have employed our sample preparation and analytical techniques with great success on the Stardust samples. We will use similar techniques on the Hayabusa samples to ensure the maximum possible scientific return.