An astronaut decides to perform an experiment to monitor how much weight he loses during his stay on the International Space Station. He weighs himself prior to takeoff, daily while on the space station, and again after returning to Earth. Explain the following for 2 points each:

Identify what data from the weights he recorded should be considered in his experiment
For any weigh-ins that should not be used in his experiment, explain your reasoning
Explain the relationship between mass, weight, and gravity