The launch, a partnership with the U.S. space agency, marks the first time a privately built spacecraft carried human passengers into orbit.
It took place at 3:22 p.m. EDT at Launch Complex 39A at NASA’s Kennedy Space Center in Cape Canaveral, Fla.
SpaceX’s Falcon 9 rocket detached from the ship after expending its fuel, and landed successfully on a drone ship in the ocean.
The spacecraft reached top speeds of roughly 27,000 kilometres per hour, according to NASA readings.
The astronauts are expected to remain in orbit for about 19 hours en route to the ISS. They are expected to arrive for an “extended stay” at the station — their return date has not yet been determined.
The flight was originally scheduled on Wednesday but was called off with just minutes on the clock due to bad weather.
Who is on board the SpaceX Crew Dragon?
Astronauts Doug Hurley, 53, and Bob Behnken, 49, are on board the Dragon.
Hurley is the spacecraft commander, and Behnken is the joint operations commander.
Hurley has been a pilot on two previous missions. Before being selected to become an astronaut 20 years ago, he was a fighter pilot and test pilot for the U.S. military.
Like Hurley, Behnken also was chosen to be an astronaut in 2000, and he piloted two space shuttle flights. He has spent more than 700 hours in space and has logged 37 hours of spacewalks, according to his NASA biography.
“SpaceX, we’re go for launch. Let’s light this candle,” Hurley said in the moments prior to liftoff.
He was paraphrasing Alan Shepard, who in 1961 became the first American to enter space.
Hurley later thanked ground control for the “great ride.”
Why is the SpaceX Demo-2 mission considered historic?
The mission represents several milestones, both for SpaceX and space flight in general.
SpaceX, which was founded nearly 20 years ago by entrepreneur Elon Musk, is the only company to launch humans into orbit so far.
It’s also joining just three countries — Russia, the U.S. and China — in achieving this milestone in space flight.
As well, the landing of the Falcon 9 marks the first time a reusable rocket has carried humans into orbit.
SpaceX says Saturday’s mission is the last major test of its system on the road to certification by NASA for contract missions to and from the ISS.
The astronauts are using SpaceX systems in orbit for the first time after a successful unmanned flight last year.
Under the Commercial Crew Program, the U.S. space agency has partnered with several companies in hopes of establishing cost-effective commercial space flight options. SpaceX has been awarded more than US$3.14 billion in contracts as part of the program.
It’s also the first time since 2011 that U.S. astronauts left Earth from the Kennedy Space Center. (Since then, U.S. astronauts have flown to the ISS in Russian spaceships launched from Kazakhstan).
The mission is also historic because it’s a stepping stone to SpaceX’s future ambitions and the overall project of commercial space travel.
The company, which wants to reduce the cost of space exploration with the help of reusable rockets, says that the mission lays the groundwork for future trips to destinations such as the moon and Mars.
U.S. President Donald Trump, who attended the launch and spoke afterward, said that America will be the first nation to land on that planet.
— With files from the Associated Press and Reuters