What do satellites “see” mostly… Here are the Grand Canyon Landsat 8 scene from the satellite_demo project (plus bands that have different cell sizes (8, 10 and 11) from the original scene found in R:\satellite\Arizona\landsat8, which didn’t get copied into the clip I made).

Answer for the visible and near and shortware infrared is mostly ILLUMINATION! The biggest difference from spot to spot isn’t the material but how much radiation is received in general. That changes for the cirrus band (9) and the thermal bands (10 & 11).

A company had a process that removed the effect of illumination using a satellite image and a DEM. Could you do that? (but they went out of business…)