The correct response is: it goes down.
The force of gravity between two objects (in this case, the astronaut and the space shuttle) depends on their masses and the distance between them, as described by Newton's law of universal gravitation. As the astronaut moves farther away from the space shuttle, the distance between them increases, leading to a decrease in the gravitational force between them. The mass of both the astronaut and the shuttle remains constant, so the only factor affecting the gravitational force in this scenario is the increasing distance.