There is one unique but smart way she can get back to her spaceship. By throwing her wrench in the opposite direction of the spaceship, she can propel herself in the direction of her spaceship. Newtons third law states "for every action there is an equal and opposite reaction" and that is used here. The astronaut pushes the wrench and it causes her to go backwards in the other direction because of the force she uses to push against the wrench.
