A mechanical thruster for positively separating two releasably joined components under a controlled time delay. The thruster is particularly useful for mechanically opening canisters containing survival kits as they are being dropped from an airplane to a target. The thruster comprises an adjustable mechanical timing means which is actuated when a pin is pulled from it. After a predetermined time delay, the timing means actuates a plunger mechanically associated with it, which plunger dislodges a locking piston. This locking piston in locking position mechanically holds a thruster body about a barrel of the device. Once the locking piston is displaced, the thruster body is propelled away from the barrel. When the mechanical thruster is secure to the main body of a container, and the thruster body is attached to the container lid, separation of the thruster body from the rest of the thruster causes the container lid to separate from the container, making it possible for the container contents to be removed from the container. The device according to the present invention can be used in place of known, pyrotechnic thruster devices.