CS78 said:
Huge amounts of high quality artillery being supplied. I assume the tacticians feel it won't be destroyed from the air?
Artillery is vulnerable to air attack but concealment from observation and supporting air defense can significantly mitigate that risk. Russia doesn't have air superiority and the Ukrainians will almost certainly have layers of MANPADS forward and S-300s behind their artillery. The Orlan--B surveillance drones and helicopters are threats that the MANPADS can handle. The S-300s will have to take on some of the fixed wing air.
Unlike what has been displayed in many photos of Russian artillery positions, disbursing the guns with at least 100m between them in a nonlinear pattern makes it difficult for enemy air to take out more than on or two guns in a single attack run with dumb bombs or rocket. Moving at night and using radar scattering camouflage netting also makes it harder to detect the artillery visually or with ground search radar.
With enough time and engineers support each gun would have a revetment berm built around it to reduce vulnerability to direct fire and fragmentation from surface burst enemy artillery.
The firebases built in Vietnam had extensive berms and sandbag walls built to protect them from ground attack and enemy artillery. Khe Sanh firebase survived a six month siege with hundreds of NVA artillery rounds impacting daily. The situation in Ukraine is different but some of the defensive preparations uEd at Khe Sanh will still be effective.