How are mass and weight measured when there is no gravity?

Answer 1

Objects always have mass whether they are in a gravity environment or not. Weight is determined by how much gravity there is.

You would take the mass and multiply by the gravitational constant of that environment. Earth is 9.8, the moon is 1.6 so you can see that your weight would be 1/6 on the moon as it is on earth.

If there is no gravity you can oscillate a spring, strap yourself to it, oscillate the spring again. Then do some fancy math to determine your mass. (saw it on a NASA video once)

Answer 2

Without gravity, mass is measured as the amount of matter in an object, which remains constant regardless of gravitational force. Weight, on the other hand, is a force that depends on gravity, so it cannot be measured accurately in the absence of gravity. The concept of weight becomes irrelevant in zero-gravity environments.