Yet, when the moment arrived, the spacecraft showed no signs of a rickety descent, eventually deploying its quad-parachute system and safely splashing down in the Atlantic Ocean some 280 miles (~450 kilometers) from its original launching spot at Cape Canaveral, Florida. The capsule then undocked from the International Space Station at 2:32 a.m. Friday after a five-day stay.
After hours of suspense, the Dragon spacecraft touched down at 8:45 am (1345 GMT) some 230 miles (370 kilometers) off the coast of the U.S. state of Florida.
It marks the first time in 50 years that a capsule designed for astronauts returned from space by plopping into the Atlantic.
While Crew Dragon will be recovered from the ocean this time, the spacecraft was designed with the ability to make powered landings using its four side-mounted "Super Draco" thrusters.
NASA has awarded SpaceX and Boeing a total of $6.8 billion to build competing rocket and capsule systems to launch astronauts into orbit.
In addition to founder Elon Musk's SpaceX, Boeing is preparing an uncrewed test flight of its Starliner craft for possible launch next month, with a crewedmission possible in August.
After five hours of free flight, SpaceX controllers jettisoned the unpressurised trunk of the spacecraft before firing the final 15 minute, 25 second deorbit burn, committing the Crew Dragon to a return to Earth. But after this week's SpaceX flight, if post-mission review determines the flight had no issues, we could see astronauts climb aboard the Crew Dragon by the end of the year.
"Fifty years after humans landed on the moon for the first time, America has driven a golden spike on the trail to new space exploration feats", NASA astronaut Anne McClain said from the station shortly after Crew Dragon departed. Like its freighter counterpart, the Crew Dragon can bring supplies back from the ISS (although not quite so much - its priority is cargo of the talking variety, of course).
NASA Administrator Jim Bridenstine hailed the splashdown, saying it "marked another milestone in a new era of human spaceflight".
It was only about a week ago that SpaceX launched the Crew Dragon, the company's first crew-capable spacecraft, towards the International Space Station. But if all goes well, the next flight will see two United States astronauts book a return trip to the ISS, sometime before the end of the year, according to NASA. After dockingat the ISS, the Canadian astronaut David Saint-Jacques was the first to enter the capsule, describing it as a "business-class" experience.
Meanwhile, Boeing is gearing up for its first unmanned test following a delay due to a fuel leak in its CST-100 Starliner spacecraft. The station's crew spent several days monitoring the spacecraft while docked to the station before closing hatches between the station and spacecraft March 7. The capsule is SpaceX's first that is created to carry humans.