Do you weigh less on Earth than in a spaceship orbiting 800 km above Earth?

No, you actually weigh slightly less in a spaceship orbiting 800 km above Earth compared to your weight on the surface of Earth. This is because weight is the force of gravity acting on an object, and gravitational force decreases with distance from the Earth's center. In orbit, you experience microgravity, which gives the sensation of weightlessness, but your mass remains the same. Thus, while you still have weight in a spaceship, it is less than what it would be on Earth's surface.