On earth you have a mass of 140kg in space you will have a mass of how many kg

140 kg. since earth and space have different gravity, you will weigh differently. you dont grow or shrink in size. Weight is just how much your pulling on the earth and how much the earth is pushing back. Its in Newtons 3 laws.

If your mass is 140kg, then your mass is 140kg.

It doesn't make a bit of difference what time it is, whether you're happy or sad, sleeping or lifting weights or running, whether it's raining or shining, hot or cold, climbing a mountain or falling out of an airplane, on the surface of a planet, asteroid, comet or star, or floating or falling through empty lonely outer space. Your mass is your mass. The only way it can change is if YOU make changes in yourSELF, like eating a big steak, sweating through a long tough workout, or skipping dinner, or growing to maturity.

(I guess you're already pretty mature. If your mass is 140kg, then you weigh about 308 pounds when you're on Earth.)