SpaceX Founder Elon Musk was almost in tears after Falcon 9 rocket successfully lifted off from NASA's Kennedy Space Center carrying a Crew Dragon spacecraft with NASA astronauts Bob Behnken and Doug Hurley on board to the International Space Station (ISS).
"I'm really quite overcome with emotion on this day, so it's kind of hard to talk, frankly. It's been 18 years working towards this goal, so it's hard to believe that it's happened," Musk said during a post-launch press conference.
"This is something that I think humanity should be excited about proud of occurring on this day," he added.
SpaceX became the first private US company to take NASA astronauts to space.
Known as NASA's SpaceX Demo-2, the mission is an end-to-end test flight to validate the SpaceX crew transportation system, including launch, in-orbit, docking and landing operations.
This is SpaceX's second spaceflight test of its Crew Dragon and its first test with astronauts aboard, which will pave the way for its certification for regular crew flights to the station as part of NASA's Commercial Crew Programme.
"This is a dream come true for me and everyone at SpaceX," said Musk, chief engineer at SpaceX.
"It is the culmination of an incredible amount of work by the SpaceX team, by NASA and by a number of other partners in the process of making this happen. You can look at this as the results of a hundred thousand people roughly when you add up all the suppliers and everyone working incredibly hard to make this day happen," Musk elaborated.