A linear actuator is disclosed. The linear actuator includes a housing, a linear output member, and a rotary lock assembly. The linear output member includes a radial groove and is axially movable from a retracted position within the housing. The rotary lock assembly is constrained from axial motion within the housing and includes a rotor and a lock. The rotor is capable of rotation from a first to a second position. When the linear output member is in the retracted position, the rotor surrounds the radial groove. When the rotor rotates to the first position, the lock engages the radial groove and prevents axial motion of the output member from the retracted position.