On a three year trip to Mars astronauts are exposed to micro-gravity. One major problem due to micro-gravity is bone loss. A NASA website states “Space travelers can lose on average one to two percent of bone mass each month.” My design is meant to measure the percentage of bone mass astronauts have. Astronauts push down on two handles like a pump. The pump measures your strength by how hard they pushed down. It is also a good way to work out in space. Astronauts are supposed to check their bone density every day. They snap the pump to the little platform with the ball and stick it to a wall on the spacecraft. Then they take the other piece and stick it to the same wall right next to the pump. The pieces are supposed to be made out of a mixture of plastic and aluminum powder. Then, they have to strap their foot in so they don’t drift off. To stay stable, the astronauts have to use the straps that are on the spacecraft.