Astronauts on a spacewalk use the Newton's third law for navigation. Newton's third law states that every action has an equal and opposite reaction. Action and reaction forces act on different bodies.If a person applies a force on an object, the object applies an equal and opposite force on the person.
The astronaut who has been detached from her spaceship, has a handy tool belt attached to her waist. If she throws a tool in a direction opposite to the direction of the location of the spaceship, the tool exerts an equal force on the astronaut, propelling her in the direction of the ship. To reach the ship, she can keep throwing tools, taking care to throw it exactly in the opposite direction in which she needs to travel.
Every time a tool is thrown backwards, the astronaut will experience a force in the forward direction in accordance with Newton's third law, ultimately enabling her to get back to the ship.