Final answer:
The size of the excavated crater primarily depends on the speed of impact. A fast projectile penetrates the target planet, generating a shock wave and heat that cause the rock to fracture and create an explosion. The size of the excavated crater is typically 10 to 15 times the diameter of the projectile.
Step-by-step explanation:
The size of the excavated crater depends primarily on the speed of impact. When a fast projectile strikes a planet, it penetrates two or three times its own diameter before stopping. The shock wave and the heat generated during the impact fractures the rock of the target, creating an explosion similar to that of a nuclear bomb detonated at ground level. The excavated crater is generally 10 to 15 times the diameter of the projectile.