WASHINGTON, Dec. 15 (Xinhua) -- Private U.S. company SpaceX took another big step in its push for reusability on Friday by launching a resupply mission to the International Space Station with a rocket and spacecraft that have both flown previously.

The liftoff, which occurred at 10:36 a.m. EST (1536 GMT) at Cape Canaveral Air Force Station in Florida, marked the first time the California-based company has re-flown both its Dragon spacecraft and Falcon 9 first stage, which were last used in April 2015 and June 2017, respectively.

"This is the beginning of rapid and reliable reusability," SpaceX's Dragon mission manager Jessica Jensen told reporters during a prelaunch briefing.

"In the long run, reusability is going to significantly reduce the cost of access to space, and that's what's going to be required to send future generations to explore the universe. You know, we want to be able to send thousands of people into space, not just tens," Jensen said.

SpaceX has already had three successful "flight-proven" Falcon 9 launches before, all of which occurred this year on commercial satellite delivery missions.

Dragon has been reused only once and it's in June this year for a similar cargo run to the space station.

But the latest mission, carrying 4,800 pounds (2,200 kilograms) of research, crew supplies and hardware, was a first for the U.S. space agency NASA.

Kirk Shireman, NASA's space station program manager, said the U.S. space agency did "an extensive review" on re-using the Falcon 9 first stage.

"We're very comfortable that the risk posture on this vehicle is not significantly greater than a new booster," Shireman said.

It's the 13th of up to 20 missions to the space station that SpaceX will fly for NASA under a multi-year commercial resupply services contract.

Among the cargo were experiments investigating muscle wasting, plant growth in low gravity, and the microorganisms inhabiting the space station, NASA said.

And as usual, SpaceX succeeded in landing Falcon 9's first stage back at its Landing Zone 1 at Cape Canaveral Air Force Station about eight minutes after liftoff.

"Falcon 9 first stage has landed at Landing Zone 1 - SpaceX's 20th recovery of a first stage booster," the company tweeted after the successful touchdown.

If everything goes well, Dragon will arrive at the space station on Sunday.