An Air Force X-37B spaceplane just completed its 718th day in orbit, making it the longest mission yet for a secretive military test program.
원문출처 : https://www.cnn.com/2019/08/27/tech/x-37b-air-force-space-plane-days-in-space-scn-trnd/index.html
원문출처 : https://www.cnn.com/2019/08/27/tech/x-37b-air-force-space-plane-days-in-space-scn-trnd/index.html