Astapov entered the military after studying at the Ryazan Guards Higher Airborne Command School, serving in a regimental reconnaissance company of the Soviet Airborne Forces. Rising through the ranks he saw service during the First Nagorno-Karabakh War, subsequently becoming commander of a paratrooper battalion after the breakup of the Soviet Union. He saw action in the First and Second Chechen Wars as deputy commander of the 21st Airborne Brigade, and later as commander of the . By the mid-2000s he was commander of the 7th Guards Mountain Air Assault Division, and after studies at the Military Academy of the General Staff of the Armed Forces, became chief of staff and first deputy commander of the Siberian Military District.