S1-M0 "Doc Simon" was a Battle droid of the Galactic Republic active during the Cold War. In 3643 BBY it was aboard the Thranta-class corvette Brentaal Star during the Attack on the Brentaal Star by the Gage-class transport Black Talon. S1-M0 was in a boarding party against that vessel, accompanied by Sergeant Boran, Corporal Hattak and Private Keemos. They defended their boarding shuttle against a counterattack by an Imperial strike team, but after were all killed.