2 ms·

Bone density is a solved problem. Daily usage of exercise machines for about 1-2 hours keeps the same density; tested on ISS astronauts. I agree that one-way t

by deletes 13y ago

Bone density is a solved problem. Daily usage of exercise machines for about 1-2 hours keeps the same density; tested on ISS astronauts. I agree that one-way trip is the best, because of difficulty to acquire fuel.