SpaceX has proven it can fly astronauts. Here's how Elon Musk's company became the first to help NASA resurrect US spaceflight.

· SpaceX returned two NASA astronauts to Earth on Sunday after flying them to the International Space Station.
· The mission, called Demo-2, flew the first crewed US spacecraft since the end of NASA's space shuttle program in 2011.
· SpaceX's Crew Dragon spaceship is a product of NASA's Commercial Crew program, a partnership...