CAPE CANAVERAL, Fla. — Four amateur astronauts lifted off from the Kennedy Space Center here Wednesday evening, making history by becoming the first all-civilian crew to reach orbit in a fully commercial mission operated by Elon Musk’s SpaceX and paid for by a billionaire entrepreneur.

The launch, dubbed Inspiration4, was the first step in what is planned to be an audacious three-day journey in orbit around Earth by a group of people who just months ago didn’t know each other and didn’t expect to fly to space.

Just before launch, Jared Isaacman, the billionaire businessman who financed the trip and is its commander, urged action. “Inspiration4 is go for launch," he said. "Punch it, SpaceX.”

Upon reaching orbit, Isaacman said, “The door is opening now, and it’s pretty incredible.”

SpaceX confirmed late Wednesday that the spacecraft had hit an altitude of about 363 miles, exceeding the intended orbit of just under 360 miles.