HOUSTON, Texas, June 3 -- NASA's Johnson Space Center issued the following news release: NASA astronaut and former U.S. Navy Capt. Chris Cassidy has retired from the agency's astronaut corps after 17 years of service. His last day at NASA was Friday, May 28. In his career, Cassidy accumulated 378 days in space. Of that time, he spent 54 hours, 51 minutes outside of the International Space Station over the course of 10 spacewalks. "It's been an amazing run," Cassidy said in a video posted to h  more