Why don't rockets burn up in thermosphere?

Rockets do not burn up in the thermosphere because they are designed to withstand extreme temperatures and pressures during ascent. The thermosphere, while hot, has very low density, which means there are fewer air molecules to create friction and heat. Additionally, rockets are built with heat-resistant materials and protective coatings that allow them to survive the intense conditions of launch and space travel. Their speed and altitude further minimize the effects of atmospheric drag as they ascend through this layer.