Sp4c. Petersen distinguished himself while serving as an armored personnel carrier commander with Company B during a combat operation against a North Vietnamese Army Force estimated to be of battalion size. During the initial contact with the enemy, an armored personnel carrier was disabled and the crewmen were pinned down by the heavy onslaught of enemy small arms, automatic weapons and rocket-propelled grenade fire. Sp4c. Petersen immediately maneuvered his armored personnel carrier to a position between the disabled vehicle and the enemy. He placed suppressive fire on the enemy's well-fortified position, thereby enabling the crewmembers of the disabled personnel carrier to repair their vehicle. He then maneuvered his vehicle, while still under heavy hostile fire to within 10 feet of the enemy's defensive emplacement. After a period of intense fighting, his vehicle received a direct hit and the driver was wounded. With extraordinary courage and selfless disregard for his own safety, Sp4c. Petersen carried his wounded comrade 45 meters across the bullet-swept field to a secure area. He then voluntarily returned to his disabled armored personnel carrier to provide covering fire for both the other vehicles and the dismounted personnel of his platoon as they withdrew. Despite heavy fire from 3 sides, he remained with his disabled vehicle, alone and completely exposed. Sp4c. Petersen was standing on top of his vehicle, firing his weapon, when he was mortally wounded. His heroic and selfless actions prevented further loss of life in his platoon. Sp4c. Petersen's conspicuous gallantry and extraordinary heroism are in the highest traditions of the service and reflect great credit on him, his unit, and the U.S. Army.