This time they did it.

After several unsuccessful attempts to land an unmanned rocket on a football field-sized floating platform in the Atlantic Ocean, Elon Musk’s SpaceX finally pulled off the dramatic feat Friday afternoon in its first launch to resupply the International Space Station since its rocket exploded last year.

The landing, the first ever of a rocket’s first stage at sea, was heralded as a breakthrough for the burgeoning commercial spaceflight industry, and its leader, SpaceX.

“It’s another step toward the stars. In order for us to really open up access to space we have to have full and rapid reusability,” Musk said at a press conference afterwards.

In December, SpaceX landed the first stage of its unmanned Falcon 9 rocket on a landing pad it has built at the Cape Canaveral Air Force Station. And Blue Origin, the space company founded by’s Jeff Bezos, has now launched and landed the first stage of its suborbital New Shepard vehicle three times. (Bezos owns The Washington Post.)

The companies’ efforts to recover their rockets is part of what Bezos calls the “Holy Grail” quest of lowering the cost of space flight, which has been so prohibitively expensive that it has long been the exclusive domain of governments.

Typically, the first stages of rockets are ditched into the ocean after firing their engines for a few minutes and boosting a second stage, or a capsule, to space.

But if the commercial sector can build innovative rockets that can be reused, many think that would dramatically reduce the costs, a key step toward making space travel more routine.

SpaceX broadcast the launch and landing live on its website, where some 80,000 viewers watched the booster descend toward the platform. The first stage was hurtling toward space when it started a bit of aerial acrobatics, turning itself around and heading back toward Earth.

As it approached the platform, the booster was tilted into the wind but was able to right itself just before touching down, about nine minutes after liftoff. Crews were expected to board the ship and secure the rocket to the platform.

“It’s quite a tiny target. It’s like trying to land on a postage stamp there,” Musk said. “It’s like a carrier landing versus a land landing.”

At SpaceX's headquarters, just outside of Los Angeles, employees broke out in raucous applause, as congratulations poured in from across the country.

Canadian astronaut Chris Hadfield and Buzz Aldrin, the second man to walk on the moon, tweeted their well wishes. "Opens the imagination to what is possible," Hadfield wrote.

President Obama also tweeted his congratulations to SpaceX, saying, "It's because of innovators like you & NASA that America continues to lead in space exploration."

Musk's ultimate goal is to colonize Mars, and his company has been gaining experience launching rockets under the lucrative NASA contracts it holds to fly cargo to the space station. Along with Boeing, SpaceX won a NASA contract to fly astronauts there by 2017, which would mark the first manned flights from U.S. soil since the shuttle was retired in 2011.

In its previous attempts to land on what SpaceX calls an “autonomous spaceport drone ship,” the rockets came close each time and hit the platforms. But each time they either crashed hard, or fell over and exploded. Musk said the company would test fire the returned rocket 10 times, and then if those go well, the company would launch the rocket on an orbital mission, perhaps as early as June.

The successful launch of the Falcon 9 from Cape Canaveral Air Force Station at 4:43 p.m. was the company’s first mission to the space station since June, when its unmanned rocket blew up a few minutes into flight. Since that catastrophic failure, SpaceX has flown three times, launching commercial and government satellites to orbit. But this was its first mission to resupply the International Space Station under its contract with NASA since the explosion.

SpaceX’s Dragon spacecraft is expected to rendezvous with the station Sunday morning. The spacecraft is filled with about 7,000 pounds of supplies and science experiments, including an expandable habitat.

The habitat has been developed by another commercial space company, Bigelow Aerospace, founded by Robert Bigelow, a wealthy entrepreneur who started Budget Suites of America. In an interview this week, Bigelow said he has invested $290 million of his own money into the company.

The habitat is packed in the trunk of the spacecraft and will be inflated once it is attached to the space station. Made of a Kevlar-like material, it is to be periodically visited by the astronauts on board the station, who will test to see how it fares in space’s harsh environment.

The habitat is expected to stay affixed to the station for two years. But ultimately, the company plans to fly its B330 habitats, which are 20 times bigger. Bigelow said he hopes that habitat could also be attached to the space station for testing ahead of plans to launch a pair of them as its own space station in 2020.

The B330 could also be used as a lunar base one day, he said.

Wondering how Falcon 9's first stage will attempt to fly back to Earth on our next launch? Image courtesy of SpaceX.