"Welcome home, baby," said SpaceX's elated chief, Elon Musk, who said the old-fashioned splashdown was "like seeing your kid come home."
He said he was a bit surprised to hit such a grand slam.
"You can see so many ways that it could fail and it works and you're like, 'Wow, OK, it didn't fail,'" Musk said, laughing, from his company's headquarters in Hawthorne, California. "I think anyone who's been involved in the design of a really complicated machine can sympathize with what I'm saying."
The goal for SpaceX, he told reporters, will be to repeat the success on future flights.
The unmanned supply ship scored a bull's-eye with its arrival, splashing down into the ocean about 500 miles (800 kilometers) off Mexico's Baja California peninsula. A fleet of recovery ships quickly moved in to pull the capsule aboard a barge for towing to Los Angeles.
It was the first time since the shuttles stopped flying last summer that NASA got back a big load from the space station, in this case more than half a ton of experiments and equipment.
Thursday's dramatic arrival of the world's first commercial cargo carrier capped a nine-day test flight that was virtually flawless, beginning with the May 22 launch aboard the SpaceX company's Falcon 9 rocket from Cape Canaveral and continuing through the space station docking three days later and the departure a scant six hours before hitting the water.
The returning bell-shaped Dragon resembled NASA's Mercury, Gemini and Apollo spacecraft of the 1960s and 1970s as its three red-and-white striped parachutes opened. Yet it represents the future for American space travel now that the shuttles are gone.
"This successful splashdown and the many other achievements of this mission herald a new era in U.S. commercial spaceflight," NASA Administrator Charles Bolden said in a statement.
Alan Lindenmoyer, manager of NASA's commercial crew and cargo program, was emotional as he turned to Musk and assured him that NASA was now his customer and that resupply services were about to unfold on a regular basis.
"You have turned those hopes into a reality," Lindenmoyer said. Noted Musk: "It really shows that commercial spaceflight can be successful. I mean, this mission worked first time right out the gate."
Musk, the billionaire behind PayPal and Tesla Motors, aims to launch the next supply mission in September under a steady contract with NASA, and insists astronauts can be riding Dragons to and from the space station in as little as three or four years. The next version of the Dragon, for crews, will land on terra firma with "helicopter precision" from propulsive thrusters, he noted. Initial testing is planned for later this year.
President Barack Obama is leading this charge to commercial spaceflight. He wants routine orbital flights turned over to private business so the space agency can work on getting astronauts to asteroids and Mars. Toward that effort, NASA has provided hundreds of millions of dollars in seed money to vying companies.
NASA astronauts are now forced to hitch rides on Russian rockets from Kazakhstan, an expensive and embarrassing outsourcing, especially after a half-century of manned launches from U.S. soil. It will be up to SpaceX or another U.S. enterprise to pick up the reins. Several companies are jockeying for first place.
It will take a few days to transport the fresh-from-orbit Dragon by barge to the Port of Los Angeles. From there, it will be trucked to the SpaceX rocket factory in McGregor, Texas, for unloading and inspection. Reports from the scene are that the spacecraft looks "really good," Musk said, with no major changes needed for future Dragons, just minor tweaks.
SpaceX - or more properly Space Exploration Technologies Corp. - plans to hustle off a few returning items while still at sea to demonstrate to NASA a fast 48-hour turnaround. That capability would be needed for future missions bearing vital experiments.
The capsule returned nearly 1,400 pounds (635 kilograms) of old space station equipment and some science samples, a little more than it took up. Because it was a test flight, NASA did not want to load it with anything valuable. It carried up mostly food.
This was only the second time a Dragon has returned from orbit. In December 2010, SpaceX conducted a solo-flying shakedown cruise. Like the Dragon before it, this capsule will likely become a traveling exhibit.
Russia's Soyuz capsules for carrying crews also parachute down but on land, deep inside Kazakhstan. All of the government-provided cargo vessels of Russia, Europe and Japan are filled with station garbage and burn up on descent.
NASA lost the capability of getting things back when its shuttles were retired last July. Rival Orbital Sciences Corp. hopes to have its first unmanned test flight off by year's end, launching from Wallops Island in Virginia. It, too, has a NASA contract for cargo runs.
The grand prize, though, will involve getting American astronauts flying again from U.S. soil and, in doing so, restore national prestige. Aboard the space station is a small U.S. flag that soared on the first shuttle mission in 1981 and returned to orbit with the final shuttle crew. It will go to the first private rocket maker to arrive with a U.S.-launched crew. After that, promises Lindenmoyer, there will be more opportunities for partnering NASA and industry - perhaps at the moon, Mars or beyond.