The launch, which carried no passengers, was to deliver 5,500 pounds of cargo and supplies to the International Space Station aboard a Dragon spacecraft. But its significance was broader.

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Launch Complex 39A is the site from which many of the Apollo astronauts — including the Apollo 11 crew of Neil Armstrong, Buzz Aldrin and Michael Collins — took off on their trips to the moon. It also hosted many shuttle missions, serving as the stage for dozens of fiery blastoffs along the Florida coast.

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But after the shuttle was retired in 2011 and interest in the United States' space program waned, 39A sat dormant as NASA contemplated an uncertain future.

NASA officials decided to lease out the launch site and found a willing tenant in SpaceX, the hard-charging venture founded by Musk, whose goal is ultimately to put humans on Mars.

If not for the arrangement, the towering pad of concrete and steel “would have wasted away in the salt air,” said NASA’s Robert Cabana, the director of the Kennedy Space Center.

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Sunday’s flight, then, was an important resurrection of the site, which is listed on the National Register of Historic Places. For SpaceX, the use of 39A reinforces its status as a leader among a group of commercial space ventures that are trying to lower the cost of space travel, and revolutionize an industry that has been stagnant for decades.

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And the mission represented another successful launch — and landing — after suffering two explosions in the last two years.

“Every launch for me is a significant emotional event. There’s not one launch where I feel comfortable and calm,” Gwynne Shotwell, the president of SpaceX said at a prelaunch briefing Friday. “They are always, always nerve wracking. I can tell you it’s an extra special launch tomorrow for sure, maybe extra nerve-racking.”

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For NASA, the flight signals an important transformation of the Kennedy Space Center, as it increasingly relies on the private sector for travel to what’s known as low Earth orbit. Several commercial companies now have contracts to fly cargo to the space station. SpaceX and Boeing also have been hired to fly astronauts there.

Jeffrey P. Bezos’s Blue Origin is leasing another launch site here. (Bezos owns The Washington Post.) Moon Express, which is vying to land a spacecraft on the moon as part of the Google Lunar X Prize, has also had a partnership with NASA to test its lunar lander at the Kennedy Space Center.

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A host of big, legacy contractors such as Boeing and Lockheed are also building NASA’s new rocket, the Space Launch System, and the Orion crew capsule, which NASA hopes will fly astronauts to the moon or Mars from here.

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All of the activity on the Florida Space Coast stands in contrast to just a few years ago when the shuttle was being retired and the Obama administration killed the Constellation program — an over-budget and behind-schedule plan to build a big rocket and spacecraft designed to go to the moon.

That “was a bleak time here at the center,” said Tom Engler, director of the NASA’s Center Planning and Development Directorate.

But times have changed, he said.

“We have four active human spaceflight programs here at Kennedy Space Center at this point in time: Orion, SpaceX, Boeing and now Blue Origin that are all going to be in the next few years taking humans to space,” Engler said. “If you put that in context of the history of human spaceflight, only three countries have ever flown humans into space: U.S., Russia and China.”

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Traditionally, the first stages of rockets were ditched into the ocean. But SpaceX has been able to successfully recover several of its boosters. Later this year it plans to re-fly one of its used boosters, which it calls “flight proven,” for the first time. SpaceX officials also said it plans to reuse a previously flown Dragon spacecraft on a future cargo mission.

This year, it plans to launch of maiden flight of its Falcon Heavy, a much more powerful rocket that has been under development for years. SpaceX plans to use the Falcon Heavy to launch its Red Dragon spacecraft to Mars as early as 2020 in an uncrewed mission.

Launchpad 39A is where the company plans to fly NASA astronauts to the station. While that was initially supposed to happen by 2017, both SpaceX and Boeing have faced delays that could push certification of their vehicles to 2019, the Government Accountability Office recently reported. But Shotwell said the company is still on track for 2018.

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SpaceX has another launch site here, pad 40. But it was damaged significantly when a Falcon 9 rocket exploded in September while being fueled ahead of an engine test.

The launch was originally scheduled for Saturday, but Musk personally called off the flight at almost the last second because of concerns about a potential mechanical problem. The Dragon spacecraft is carrying several experiments, including an instrument that would monitor the health of the ozone layer, a sensor that would study lightning from space and a study of the growth of certain types of stem cells in microgravity.