KENNEDY SPACE CENTER, Fla. — It’s official: NASA and SpaceX have been given the go-ahead for Wednesday’s historic launch, but Mother Nature may have other plans.

Spectrum News weather experts are in agreement with the 45th Space Wing forecasters: stormy weather could dampen launch plans.

Forecasters had put the odds of acceptable launch weather at 40 percent, but on Tuesday morning, they upped the odds to 60 percent favorable.

“When it comes to space launches, there is an element of uncertainty, and we are all doing everything we can that we take that uncertainty away as much as possible,” NASA’s Administrator Jim Bridenstine said.

SpaceX tweeted Tuesday morning that the "weather forecast for launch is 60% favorable."

The technology is ready, and the SpaceX Falcon 9 rocket is good to go. But weather conditions have to be just right for the split-second launch window Wednesday afternoon. The launch window opens at 4:33 p.m. EDT.

Excitement Grows on the Space Coast

John Posey is a NASA Spacecraft lead engineer who worked for the space agency in the final days of the space shuttle.

"There was definitely a lot of apprehension about what was going to happen," said Posey.

It was a worrisome time for NASA when no replacement program was certain, until a move towards privatization.

"The whole excitement was building when we had this whole new paradigm under Commercial Crew Program," Posey said.

Fast forward to today and the first crewed flight of that program.

Two NASA astronauts , Bob Behken and Doug Hurley, are about to launch into the history books on a private SpaceX Falcon 9 inside a Crew Dragon capsule, a feat Posey helped happen.

"We were really privileged to be able to work so closely with SpaceX that we could see things evolve, and go see it first hand," Posey said.

"This is a unique moment, where all of American can take a moment and look at our country do something stunning again," said NASA Administrator​ Jim Brindenstine.

A final joint NASA and Space X Flight Readiness Review gave the go-ahead for the Demo-2 launch. The astronauts went through a final dress rehearsal over the weekend.

Due to Tuesday's weather, the Falcon 9 and Crew Dragon were lowered on Pad 39A for much of the day, but then put back in place Tuesday afternoon.

NASA leaders say this historic Commercial Crew Program test flight lays the foundation for future human spaceflight to the moon, Mars and beyond.

"It's an era in spaceflight where more space is going to be available to more people than ever before," said Brindenstine. "We envision a future where low Earth orbit is entirely commercialized, where NASA is one customer of many customers."

Posey says that future is bright for any budding engineers who want to follow in his footsteps.

"Do everything you can, and don't give up," said Posey.