Table 2.
Sand Grain Size Ranges Observed in Select MAHLI Images That Were Acquired of Sand Targets Near High Dune and on Namib Dune
| Target (sol#_name) | Image Scale (μm/Pixel) | Type | Typical Grain Size Range (Diameter of Long Axis; μm)a | Additional Notes |
|---|---|---|---|---|
| High Dune Samples | ||||
| 1182_Warsaw | 18.9 | undisturbed, ripple | 150b–900 | |
| 1182_Weissrand | 21 | track | 40c–200 | |
| 1184_Barby | 22.5 | undisturbed, ripple | 150–600 | Also, two 800–900 μm size grains |
| 1184_Kibnas | 25.9 | undisturbed, trough | 50c–400 | One 3 mm clast, a light‐toned rock fragment |
| Namib Dune Samples | ||||
| 1226_GB cand. Scoop site #2 | 20.7 | APXS touch | 40–500 | one ~1 mm grain that looks like a broken off rock clast |
| 1242_Otavi | 16 | undisturbed, ripple | 60–450 | |
| 1228_GB wheel scuff | 16.7 | scuff | 80–350 | |
| 1241_GB_discardA | 15.7 | processed to <150 μm | 45–250 | |
| 1230_GB_discardB | 17.4 | processed to >150 μm | 80–420 | some finer grains on lower left, off of discard pile |
| 1242_GB_discardC | 16 | processed to 150 μm to 1 mm | 50–600 | |
| 1242_GB_discardD | 16.4 | processed to >1 mm | 80–500 | rare <60 μm grains |
| 1253_GB_discardE | 21.4 | processed to <150 μm | 40–200 | two ~300 μm spherical grains |
| 1253_GB_discardF | 22.1 | processed to >150 μm | 100–500 | one ~1 mm grain |
a
Each MAHLI image product has an associated μm/pixel scale in the header, calculated from the distance to target and focus. Size was measured for the ~15 largest and ~15 smallest grains in the images to obtain the minimum and maximum. Because most grains are quasi‐spherical, the long axis is typically similar the average axis.
b
Some grains in between larger grains may be below the limit of resolution.
c
Some grains are below the limit of resolution.