What makes an astronaut weight less on the moon than on earth?

An astronaut weighs less on the Moon than on Earth due to the Moon's lower gravitational force. Gravity depends on both the mass of the celestial body and the distance from its center; the Moon has about 1/6th the gravity of Earth because it has significantly less mass. This reduced gravitational pull means that objects, including astronauts, experience less weight on the Moon. Consequently, while their mass remains the same, the force of gravity acting on them is weaker, resulting in a lower weight.