Dartmouth researchers have a project aboard the Polaris Dawn mission they hope will help address two major health risks of space flight—the breakdown of astronauts’ bones in zero-gravity conditions and the resulting danger of developing kidney stones. Dartmouth researchers have a project aboard the Polaris Dawn mission they hope will help address two major health risks of space flight—the breakdown of astronauts’ bones in zero-gravity conditions and the resulting danger of developing kidney stones. Space Exploration Phys.org – latest science and technology news stories