The SpaceX Inspiration 4, carrying an all-civilian crew, has landed back on earth after completing its three-day trip to space.

According to SpaceX, following the splashdown, the commander of the mission, Jared Isaacman, explained, "That was a heck of a ride for us, and we're just getting started." 

Meanwhile, founder of the Aerospace giant Elon Musk congratulated the crew, tweeting: "Congratulations Inspiration4."

The SpaceX Dragon capsule parachuted into the ocean just before sunset, not far from where their chartered flight began three days earlier.

The all-amateur crew was the first to circle the world without a professional astronaut.

The billionaire who paid undisclosed millions for the trip and his three guests wanted to show that ordinary people could blast into orbit by themselves, and SpaceX founder Elon Musk took them on as the company’s first rocket-riding tourists.

SpaceX’s fully automated Dragon capsule reached an unusually high altitude of 363 miles (585 kilometres) after Wednesday night’s liftoff. Surpassing the International Space Station by 100 miles (160 kilometres), the passengers savoured views of Earth through a big bubble-shaped window added to the top of the capsule.

The four streaked back through the atmosphere early Saturday evening, the first space travellers to end their flight in the Atlantic since Apollo 9 in 1969. SpaceX’s two previous crew splashdowns — carrying astronauts for NASA — were in the Gulf of Mexico.

This time, NASA was little more than an encouraging bystander, its only tie being the Kennedy Space Center launch pad once used for the Apollo moonshots and shuttle crews, but now leased by SpaceX.

The trip’s sponsor, Jared Isaacman, 38, an entrepreneur and accomplished pilot, aimed to raise $200 million for St. Jude Children’s Research Hospital. Donating $100 million himself, he held a lottery for one of the four seats. He also held a competition for clients of his Allentown, Pennsylvania payment-processing business, Shift4 Payments.

Joining him on the flight were Hayley Arceneaux, 29, a St. Jude physician assistant who was treated at the Memphis, Tennessee hospital nearly two decades ago for bone cancer, and contest winners Chris Sembroski, 42, a data engineer in Everett, Washington, and Sian Proctor, 51, a community college educator, scientist and artist from Tempe, Arizona.

With inputs from the Associated Press