WASHINGTON − Elon Musk and Sen. Mark Kelly, D-Ariz., traded jabs on social media Monday, after the billionaire space entrepreneur called the former NASA astronaut a "traitor" for his recent trip ...

Dr. Mason was a principal investigator for NASA’s Twins Study ... retired astronaut Sen. Mark Kelly, D-Ariz., who remained on Earth. "We saw gene expression change, which is how genes are ...