Alfonso is satisfied with the scientific samples we have collected over the past two days and gives us the day off to search for drilling samples to ship home. Daniel and I walk back up to The Wall and inspect several salt boulders that have fallen from the exposed rock face above. We measure them to see if they will fit inside the coolers that will be used to ship them home to the US for drilling tests. We select one with clear, transparent faces and begin trimming it with the percussive hammer chisel to fit in the cooler. Alfonso helps us select a medium-sized polygon that has popped loose from the ground. We put both in the back of a pickup truck alongside the other gear that we are bringing back down to camp.
Next, we decide to test a custom 1” diameter auger with a full-faced bit to see how it will drill in a polygon. The auger is 143 cm long and the drilling goes very quickly. This auger has a deep flute and moves cuttings to the surface very efficiently. The drilling does not require much force beyond the weight of the drill and no jamming of the bit is evident. We drill the entire hole without pulling out to see if the bit will get stuck but it does not. One person can pull it out without assistance. Adapting some features of the auger to a refined coring bit could improve coring performance.
Although industrial coring equipment could certainly be used to collect high quality samples much more quickly and efficiently than our handheld equipment, the point here is not to depart too far from sampling techniques that could be used on Mars with present-day technology. The results of these field trials will help us learn how and where to look for biological markers on Mars, using satellite and aerial imagery combined with ground sampling and analysis aboard a robotic rover.