Charles Stark Draper (AP) _ Charles Stark Draper, who founded the laboratory that developed guidance systems used in the Apollo moon explorations and strategic missiles, died Saturday. He was 85.

Draper, known as the father of inertial navigation, never fully recovered from a stroke he suffered some months ago, Kathleen C. Granchelli of Draper Laboratory Inc. said Sunday.

Draper developed the theory and technology of inertial navigation, which operates without relying on external sources, and helped bring it to use in aircraft, submarines, missiles and space vehicles. In the late 1950s, he earned the title ''Mr. Gyro'' because of his persistence in using the gyroscope to navigation, guidance and control instruments, gunsights, gun- bomb-rocket sights and fire control systems.

The Air Force applied Draper's work on inertial guidance for intercontinental ballistic missiles.

Since 1957, Draper Laboratory has developed guidance systems for the U.S. Navy's Fleet Ballistic Missiles - the Polaris, Poseidon, Trident I and, currently, the Trident II system.