SpaceX launch key step to reach Moon, Mars: NASA

The SpaceX Crew Dragon spacecraft carrying NASA astronauts Robert Behnken and Douglas Hurley was on its way to the orbiting laboratory in the space.

"Today a new era in human spaceflight begins as we once again launched American astronauts on American rockets from American soil on their way to the International Space Station, our national lab orbiting Earth," said NASA Administrator Jim Bridenstine.

"The launch of this commercial space system designed for humans is a phenomenal demonstration of American excellence and is an important step on our path to expand human exploration to the Moon and Mars," he said in a statement post-launch.

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.

The programme demonstrates NASA's commitment to investing in commercial companies through public-private partnerships and builds on the success of American companies, including SpaceX, already delivering cargo to the space station.

"It's difficult to put into words how proud I am of the people who got us here today," said Kathy Lueders, NASA's Commercial Crew Programme manager.

The SpaceX Crew Dragon spacecraft is scheduled to dock to the space station at 8 p.m. (India time) on Sunday.

After successfully docking, the crew will be welcomed aboard the International Space Station, where they will become members of the Expedition 63 crew, which currently includes NASA astronaut Chris Cassidy.

The crew will perform tests on Crew Dragon in addition to conducting research and other tasks with the space station crew.

The Demo-2 mission is the final major test before NASA's Commercial Crew Program certifies Crew Dragon for operational, long-duration missions to the space station.