When sitting at rest on the Moon, an astronaut experiences a weight force and a normal force, similar to sitting on Earth but with reduced gravity. The gravitational acceleration on the Moon is approximately one-sixth that of Earth due to its smaller mass and diameter. Although the astronaut is not moving, they still exert a downward force equal to their weight, which is the product of their mass and the Moon's gravitational acceleration. Therefore, a 50 kg astronaut would exert a downward force of about 83.3 N while sitting at rest. Understanding these forces helps clarify the dynamics of objects in different gravitational fields.