January 29, 2005

"It is getting to be a bit like Apollo all over again"

Space.com has another one of those articles that seems obvious - once you think about it. This time, it's the need for simulated moon dirt.

This time, when we go back to the moon, it'll be to stay. It's good practice for Mars and beyond, not to mention how much easier it'll be to mount further exploration missions from there compared to the deep gravity well on Earth. Obviously, we're going to need ways to produce what we need from the materials available on the lunar surface. Also obviously, that means devising nifty machines to do all that scientifical magic that creates those things we'll need. You gotta test those machines and methods beforehand, hence the not-so-obvious need for fake moon regolith (dirt).

Tons of lunar simulant, called JSC-1, were produced years ago under the auspices of NASA’s Johnson Space Center, hence the name. Made from volcanic ash of basaltic composition, JSC-1’s composition mimicked many of the attributes of lunar mare soil samples.

But now supplies are largely gone, with some of the material even hoarded by some researchers due to its scarceness.

We never had all that much genuine lunar soil, and there are also some limitations besides the amount available. Harrison "Jack" Schmitt walked on the moon with Apollo 17, and was the only actual geologist to go.

“The main problem with this Apollo material is that it no longer is in extremely hard vacuum and has not been for thirty-three-plus years. Also, the samples and fractions taken from it for analysis have been agitated by handling and splitting and have lost significant amounts of solar wind volatiles,” Schmitt explained.

In other words, even our original moon samples aren't precisely what was collected more than three decades ago. Like most things, regolith is changed by the environment it exists in and by the handling it sustains.

The first lunar simulant 'MLS-1' was made because it had an approximate chemistry to Apollo 11 soil 10084, but its mineralogy and engineering properties were all off. Subsequent attempts to duplicate grain-size distribution and glass content were not adequate. But, this was used by many investigators, most of whom unknowingly were not using a good simulant.

Later simulants were much better, but there is still room for, and a need for improvement. They're not exactly sure how much they'll need, but it will be measured in tons. There's money to be made in fake moon dirt.

Posted by Ted at January 29, 2005 09:14 AM
Category: Space Program
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