A person's mass would not change before, during, or after a trip to Saturn, unless he gained or lost some weight as a result of unrelated eating habits, because mass doesn't depend on an object's location, gravitational environment, color, cost, texture, temperature, political affiliation or gender orientation.
A person's mass remains constant regardless of traveling to Saturn, as mass is the amount of matter in an object. However, their weight would increase due to Saturn's stronger gravitational force compared to Earth's. For example, a 70 kg person would weigh about 731.1 N on Saturn, compared to about 686.7 N on Earth.
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