This was very localized in the regions where the astronauts worked extensively, in these areas, the astronaut bootprints darkened the lunar regolith [ or soil ] slightly, causing the regolith to absorb more sunlight and heat up. This was a region 50 to 100 meters across in the experiment deployment zone and of similar or smaller sizes at the sample collection stops. Outside of these zones, the astronauts had little or no effect on the subsurface temperatures.