Strata-1 Image Analysis: Understanding Granular Dynamics of Regolith Materials

Understanding the behavior of regolith on planetary and asteroid surfaces is vital for enabling the next stages of solar system exploration. The Strata-1 experiment aims to better understand the granular dynamics of regolith simulants in microgravity and vacuum environments. Strata-1 consists of four evacuated tubes of regolith simulant material (carbonaceous simulant, crushed and sieved meteorite, glass shards, and glass spheres) which were flown on the ISS; data consisted of images and accelerometer data. The spheres and shards tubes contain three sizes of objects, color-coded such that RGB analysis can be used to track the visibility (coverage) of these particles over time. We will present results from the initial data analysis of the Strata-1 images for the spheres and shards tubes. Previous image analysis code was developed for the shards data which has now been expanded to be applicable to the spheres data. Additional improvements have been made to the efficiency of the code, and the formatting of the data and results was updated for more definite data stages and better replicability. We track the distribution of the particle sizes (colors) by the amount of coverage over time for the spheres and shards tubes. In the spheres tube, we see that the small/red spheres cover the field of view for the majority of the experiment due to interactions with the wall, but we are able to identify some variations and small spikes in the medium/blue and large/green spheres coverages. The data regarding spheres coverages is compared to the shards coverages to determine any notable differences between the behavior of the smooth versus jagged particles. A preliminary comparison indicates that the shards tube experiences more variability in coverage over time, likely due to electrostatic charge encouraging the smallest spheres to cling to the surface of the tube, biasing the spheres data towards a higher red coverage. However, we are still able to look for overall trends and significant changes. The spikes and dips in coverages are also being compared to the events identified from the ISS accelerometer data to identify possible trends in acceleration profiles (due to motion of the ISS, internal activity, other experiments, etc., which can cause a change in acceleration) coincident with observed changes in the granular material distributions.