Hi, Could somebody please explain to me why lunar "soil" simulants JSC-1 and JSC-1A contain about 3% of ferric oxide while real lunar regolith do not have any ferric iron? Thank you, Igor Brown, PhD
Igor Brown It depends on what you want to simulate. For example, if you want to test the mechanical properties for driving a rover on, then the chemistry/mineralogy may be irrelevant.
Alan F Rawle At this time I am curious why did the authors of JSC-1(1A) lunar simulant include Fe2O3 in their composition? Unfortunately, D.S. McKay is no longer with us, and I was unable to reach C.C. Allen. So, I hope on the help of Lunar mineralogy veterans.
Igor Brown Adding another component may allow a certain property to be better simulated. A simulant does not have to (and cannot) reflect every aspect of the lunar regolith and there have been many simulants over the years. Besides there's no air or water on the moon so no erosion (or oxidation, as you infer) also. This means that particles can be highly angular (not smoothed by erosion) and spheres of glassy or metallic (e.g. Fe) can also be found. Thus the real lunar regolith if shipped to earth would not perform as it actually would when on the moon. (And about 70% of the moon rocks/regolith returned by the Apollo missions still remains in storage and not investigated). Many years ago I worked on the topic with NASA and USGS. Here's a webinar on the subject (free registration required):
The particle size and shape analysis of NASA/USGS lunar simulant
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W110714ParticleSizeShapeNASA-USGS.html
Look at the slide at about 14:22 in the talk for a definition of lunar regolith simulant.
Note that it is proposed to getting oxygen from the moon by mining and decomposing ilmenite, FeTiO3 - this has iron in the +2 oxidation state (ferrous not ferric though). See:
https://ntrs.nasa.gov/citations/19910015055
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