SpaceX's Dragon capsule, the first privately owned and operated spacecraft to be certified by NASA for human spaceflight, arrives at the International Space Station carrying four astronauts. Read more: https://wapo.st/32OrLmg. Subscribe to The Washington Post on YouTube: https://wapo.st/2QOdcqK Follow us: Twitter: https://twitter.com/washingtonpost Instagram: https://www.instagram.com/washingtonpost/ Facebook: https://www.facebook.com/washingtonpost/