SpaceX, the private rocket company of billionaire entrepreneur Elon Musk, launched two Americans into orbit from Florida on Saturday in a landmark mission marking the first spaceflight of NASA astronauts from US soil in nine years.

A SpaceX Falcon 9 rocket lifted off from the Kennedy Space Center at 3.22pm EDT (3.22am in Malaysia), launching Doug Hurley and Bob Behnken on a 19-hour ride aboard the company's newly designed Crew Dragon capsule bound for the International Space Station.

Just before liftoff, Hurley said, “SpaceX, we’re go for launch. Let’s light this candle,” paraphrasing the famous comment uttered on the launch pad in 1961 by Alan Shepard, the first American flown into space.

Minutes after launch, the first-stage booster rocket of the Falcon 9 separated from the upper second-stage rocket and flew itself back to Earth to...