Updated at 6:55 p.m. ET
NASA astronauts are heading to space from U.S. soil for the first time in nine years, aboard SpaceX's Dragon capsule, the maiden crewed flight of the innovative spacecraft.
The mission, which is sending Doug Hurley and Bob Behnken to the International Space Station, is a bold new venture for the space agency's plan to allow commercial companies to take its astronauts into low-Earth orbit.
"Let's light this candle," Hurley said moments before ignition, borrowing words uttered by America's first astronaut, Alan Shepard, in 1961.
The duo left a fiery plume behind at Kennedy Space Center's Pad 39A at 3:22 p.m. ET as they rode SpaceX's Falcon 9 rocket toward a rendezvous with the station, which will take about 19 hours. On Wednesday, storms and a tornado warning upended a launch attempt, with the veteran space shuttle astronauts suited up and strapped into the Dragon before the mission was scrubbed.
Similar weather concerns dogged Saturday's launch and nearly forced a second delay, but NASA and SpaceX decided early Saturday that conditions were trending in the right direction. As the countdown narrowed, the weather continued to improve.
The Falcon 9 booster separated and guided itself to a successful landing on a drone ship stationed in the Atlantic. Crew Dragon separated from the rocket at 3:35 p.m. ET and entered orbit.
"It was incredible. Appreciate the great ride to space," Hurley told flight controllers as the spacecraft reached orbit.
The mission marks the first time NASA has sent astronauts into space from U.S. soil since the end of the shuttle program in 2011. For nearly a decade, it has been relying on Russian Soyuz rockets to get them there. It is also a first for SpaceX, which has ambitions of someday taking paying customers zooming around the Earth.
"It's incredible, the power, the technology," said President Trump, who was at Kennedy Space Center in Florida for the launch.
"That was a beautiful sight to see and I hope you all enjoyed it," the president said.
Speaking at a post-launch news conference on Saturday, NASA Administrator Jim Bridenstine said: "What a great day for NASA. What a great day for SpaceX. What a great day for the United States."
"I'm really quite overcome with emotion on this day, so it's kind of hard to talk, frankly," he said.
Elon Musk, the billionaire founder and CEO of SpaceX, called it "a day that I think everyone can be proud of."
"This event is something that all of humanity can get excited about," he said.
Hurley, 53, and Behnken, 49, will put the bell-shaped Dragon through its paces on the way to the station. Dragon, which on the surface resembles an updated Apollo-era command module, sports a sleek interior and oversized touchscreen controls. Its SpaceX Falcon 9 booster has been used successfully dozens of times to put satellites and space-station cargo into orbit.
The Dragon-Falcon 9 configuration is a far cry from the winged space shuttle, but the SpaceX capsule has considerable safety advantages. Unlike the shuttle, it sits on top of the rocket, therefore avoiding debris that can fall off during launch and potentially damage the spacecraft — a problem that doomed the space shuttle Columbia in 2003. The position also makes it easy to eject the capsule if the rocket itself runs into trouble.
That's not to say that SpaceX hasn't had safety issues over the years. In 2015, one of its uncrewed rockets exploded on the way to the space station. But overall, SpaceX has enjoyed a good track record in its eight years of flying cargo to the space station.
SCOTT SIMON, HOST:
Later today, NASA and the commercial company SpaceX is scheduled to do something that hasn't been done in nearly a decade - launch astronauts to the International Space Station aboard an American rocket. We're joined now by NPR science correspondent Geoff Brumfiel. Geoff, thanks so much for being with us.
GEOFF BRUMFIEL, BYLINE: Good morning, Scott.
SIMON: Remind us. I happened to be there for the last time that Americans launched into orbit from U.S. soil.
BRUMFIEL: Right. Well, if you were there, then you remember it was the space shuttle Atlantis, and that was way back in 2011 now, almost a decade ago. The shuttle was retired that year. And since then, American astronauts have been getting to space, but they've been doing it on Russian rockets. They've been launching from Kazakhstan on Soyuz rockets. So this is going to be a big change.
SIMON: And this launch is different than the shuttle, isn't it?
BRUMFIEL: Yeah. It looks completely different. So this is a spacecraft called Dragon. Unlike the shuttle, it's really small. It's got sort of this white, shiny exterior, and on the interior, there's touchscreen controls and stuff. But it actually also looks kind of like a throwback. It's like this bell-shaped capsule kind of like the Apollo era. And it sits way up on top of the rocket rather than being strapped to the side the way the shuttle was. And this really marks a return to that older kind of safer way to get to space. The shuttle was big, and it was below its fuel tanks, which could cause the wings to get damaged. And it used both solid and liquid-fueled rockets. It was this really complicated design, and this is hopefully simpler and safer.
SIMON: NASA has to keep a close eye on the weather today, doesn't it?
BRUMFIEL: Yeah. I mean, Florida weather, it's always a problem for NASA. They were all set to go actually on Wednesday. The astronauts were strapped in, and they waited through thunderstorms, even a tornado warning. But in the end, they had to stand down because the weather looked just a little too dangerous. And it's not just the weather at the launch site. If anything goes wrong on the way up, the astronaut capsule will actually eject from the top of the rocket and land in the ocean. So they have to have good conditions in the Atlantic along most of the flight path so that they can be rescued safely. Mother Nature's actually going to be the deciding factor on whether we see a launch later today.
SIMON: Geoff, has the pandemic changed anything about this trip?
BRUMFIEL: Well, NASA astronauts Bob Behnken and Doug Hurley have been in quarantine, but that's not unusual. Astronauts always go into quarantine a few weeks before a space launch. But there are some really big differences on the ground. It was really clear how things had changed during the run-up to that aborted launch on Wednesday. The ground crew were all wearing masks. Even Elon Musk, the billionaire who started SpaceX, he's been really skeptical of the whole COVID-19 pandemic, but he was wearing a mask. And there's other changes, too. They're using multiple control rooms to spread out the ground crews. They're making sure in mission control everyone's 10 feet apart. In short, they're trying to make this a safe workplace on Earth.
SIMON: Geoff, how can people see the launch?
BRUMFIEL: Well, NASA is asking people to stay away. They don't want crowds gathering because they're obviously worried about the possibility the coronavirus could spread. But the whole thing is going to be streamed online through NASA's website and on YouTube. So you can watch there. The launch is scheduled to happen at 3:22 p.m. on the dot today. And if it doesn't happen today because of weather, they'll try again tomorrow.
SIMON: NPR's Geoff Brumfiel, thanks so much.
BRUMFIEL: Thank you, Scott. Transcript provided by NPR, Copyright NPR.