The launch has been called off for the day, less than 20 minutes before scheduled liftoff from the Kennedy Space Center in Florida, due to inclement weather. It has been rescheduled for Saturday, May 30, at 3:22 p.m.
ABC’s Mark Remillard reports for ABC News Radio:
If all goes well on Saturday, the SpaceX Demo-2 launch will send NASA astronauts Robert Behnken and Douglas Hurley to the International Space Station on a Crew Dragon spacecraft propelled by a Falcon 9 rocket.
The launch is historic in part because it ends a nearly 10-yearlong U.S. dependency on Russia for seats to space. It also marks the first time Elon Musk's private space firm, SpaceX, is launching astronauts.
Here is the latest on the milestone launch for the U.S. space program Wednesday. All times Eastern.
6:00 p.m.: Jim Bridenstine says there was 'too much electricity in the atmosphere'
The NASA administrator gave brief remarks Wednesday evening after the astronauts had dismounted the spaceship.
"I know there’s a lot of disappointment today, the weather got us,” Jim Bridenstine said. Still, he called it "a great day" for NASA and SpaceX, lauding how the teams "worked together in a really impressive way."
Bridenstine said ultimately, there was "too much electricity in the atmosphere."
"There wasn’t really a lightning storm or anything like that, but there was a concern that if we did launch it could trigger lightning," he said. "In the end the right decision was made."
He called Wednesday's called-off launch a "milestone" in its own right, saying they learned a lot from a full "wet dress rehearsal."
Bridenstine said he is proud of the teams and that on "Saturday afternoon, we are going to do it again."
"Here’s what we know, we are going to launch American astronauts on American rockets from American soil," he said. "We’re very close."
5:28 p.m.: Trump says he will be back for the launch on Saturday
President Donald Trump tweeted his thanks to NASA and SpaceX for their "hard work and leadership."
The president, who had flown down for the scrubbed launch today, added that he will be back on Saturday for the rescheduled launch.
5:00 p.m.: Jim Bridenstine to provide remarks on today’s scrubbed launch at 5:20 p.m.
The NASA administrator announced on Twitter that they will hold a briefing at around 5:20 p.m., after Behnken and Hurley have exited the Crew Dragon.
4:17 p.m.: Launch scrubbed for the day due to weather
With approximately 20 minutes until liftoff, the launch has been called off for the day due to inclement weather.
There were three weather constraints that prevented liftoff today, including natural lightning, NASA officials said in a broadcast. Unfortunately, they expected all the inclement weather conditions to clear up just 10 minutes after the scheduled launch time today.
While it has been called off for today, the historic launch has been rescheduled for 3:22 p.m. ET on Saturday, May 30.
As of Wednesday morning, the launch mission's executive forecast for Saturday predicted a 40% probability of violating weather constraints. If weather also impedes Saturday's launch, the astronauts and team will try again on Sunday.
3:54 p.m.: Launch escape system is armed, ready for propellant loading
The launch escape system is armed and it’s a “go” for loading the fuel, it was announced on NASA’s broadcast.
With liftoff less than an hour away, currently, all systems are a “go” except for the weather.
3:35: Weather at Kennedy Space Center remains an issue
Less than an hour before launch, it remains unclear if the weather will clear up enough for the launch to go through today.
At just past 3:30 p.m. ET, NASA said the range for weather was still “red,” meaning they can’t launch under these conditions.
NASA is currently launching balloons to check conditions.
A “Go, No Go,” count is expected at 3:48 p.m. ET.
In the morning, the launch mission's executive forecast predicted a 50% probability of violating weather constraints.
3:25 p.m.: How the mission is honoring the Class of 2020
The 100,000 images of recent graduates were compiled together into the image of planet earth.
“Congratulations to all of our 2020 graduates!” NASA said in a tweet.
3:05 p.m.: Chris Cassidy shares message from the ISS
NASA Astronaut Chris Cassidy, the lone American currently aboard the ISS, said he will be watching the the arrival of his "friends" Benkhen and Hurley from out of his window.
"I’m very excited that two close friends will be arriving and joining the crew," Cassidy said. "I can’t tell you how exciting it is to know that we’re once again launching Americans from the coast of Florida."
"I can't wait to look out the window and see my friends on close approach," he said. "Go Bob and Doug, I'll see you soon."
2:45 p.m.: Air Force One flies over launch site
Air Force One, carrying President Donald Trump, was seen in NASA's live broadcast arriving at the launch site.
The president is flying in to watch the launch, which is currently less than two hours away.
The last president to witness a launch from the Kennedy Space Center was Bill Clinton in October 1998.
2:20 p.m.: Elon Musk calls launch 'a dream come true,' shares what he said to astronauts
In comments on NASA's broadcast of the launch, SpaceX CEO Elon Musk called the day "a dream come true" for him and everyone at SpaceX.
"When starting SpaceX in 2002, I really did not think this day would occur," Musk said.
He called the day the culmination "of 100,000 people working incredibly hard to make this day happen."
NASA Administrator Jim Bridenstine added that "a lot of folks said it couldn't be done."
"SpaceX can do things that NASA historically has not done," Bridenstine said, noting how the private space company will "test, fail, fix, fly" until everything is in order ahead of the historic launch with astronauts today.
Musk said he felt extra responsibility when he saw the astronaut's family members.
Musk said he told the astronauts, "we've done everything we can to make sure you guys come back okay."
2:10 p.m.: Astronauts wrap up communications check
After strapping into their seats, Behnken and Hurley did a series of communications checks from inside the spacecraft.
All systems appeared to be working and the astronauts could communicate clearly with the teams on the ground.
From inside the capsule, Hurley said they are "feeling great" ahead of the launch.
2:00 p.m.: Astronauts get strapped into the capsule
After giving "air hugs" to their friends and family, Behnken and Hurley strapped into their seats in the Crew Dragon.
Vice President Mike Pence, donned in a mask, also greeted the astronauts and their families as they headed into the Crew Dragon.
1:50 p.m.: Astronauts suit up and head to the launch pad
Behnken and Hurley suited up ahead of the launch, in the same room where the first crewed Apollo mission astronauts got into their gear.
“The suit is really one part of the bigger Dragon system, it’s really part of the vehicle,” Chris Trigg, SpaceX’s space suits and crew equipment manager said. “The suit and the seat are working together.”
The suits were designed by SpaceX’s team in California.
12:45 p.m.: Weather forecast for launch includes chance of showers, possible thunderstorms
The weather forecast ahead of the launch in Cape Canaveral, Florida, includes a chance of some showers, possible thunderstorms, and potentially, some electrically charged clouds.
Major weather concerns ahead of the launch are rain and lightning. Residual electrical charges from leftover thunderstorms might interact with the rocket which has a charge itself as it goes through the troposphere and can cause trigger lightning, according to ABC News' chief meteorologist Ginger Zee.
As of Wednesday morning, the launch mission's executive forecast predicted a 50% probability of violating weather constraints.
NASA Administrator Jim Bridenstine tweeted just after noon on Wednesday that they will continue monitoring downrange weather, but are still proceeding towards a 4:33 p.m. launch.
"We are a go for launch!" Bridenstine wrote.