SpaceX, NASA, astronauts making final preparations: 'We're go for launch'

CAPE CANAVERAL, Fla. - SpaceX is making final preparations for Wednesday's Demo-2 mission to launch NASA astronauts from U.S. soil for the first time since 2011. A SpaceX Falcon 9 rocket and Crew Dragon spacecraft will transport astronauts Doug Hurley and Bob Behnken to the International Space Station on the historic mission.

NASA Administrator Jim Bridenstine said he texted the two astronauts Monday and told them, “`If you want me to stop this thing for any reason, say so. I will stop it in a heartbeat if you want me to.' They both came back and they said, ‘We’re go for launch.’”

Hurley and Behnken are scheduled to launch at 4:33 p.m. EDT from launch pad 39A of the Kennedy Space Center in Florida, which was also used for the Apollo and space shuttle programs.

The launch will be the first time a private company, rather than a national government, sends astronauts into orbit.

“Team is performing additional pre-flight checkouts of Falcon 9, Crew Dragon, and the ground support system ahead of tomorrow’s Demo-2 mission,” SpaceX tweeted earlier Tuesday. The weather forecast for launch is 60 percent favorable, SpaceX added.

Previous forecasts had put the weather at 40 percent favorable.

“Dragon Dawn,” tweeted SpaceX CEO Elon Musk, with a time-lapse video of Crew Dragon on the launch pad next to the access arm that Hurley and Behnken will use to board the spacecraft.

“I’ve often said that our astronauts are the best America has to offer,” Bridenstine tweeted Tuesday. Hurley and Behnken, he added, “are truly the best of us.”

The launch is eagerly anticipated.

“Looking forward to tomorrow’s historic mission – it’ll be a day all Americans and space fans everywhere will never forget! T minus 1 day and counting!,” Apollo 11 astronaut Buzz Aldrin tweeted Tuesday.

Speaking during a news briefing Tuesday, Bridenstine described the launch as “a unique opportunity” to bring all of America together in one moment in time.

Both NASA and SpaceX have been diligent about making sure everyone in the launch loop knows they're free to halt the countdown if there's a concern, Bridenstine added.

Take a look at the Falcon 9 rocket and Crew Dragon spacecraft

Astronauts will ride aboard the vessel in the first manned U.S. space mission in nearly 10 years.

Some 45 seconds from liftoff the SpaceX launch director will give the final go after everyone has been polled on Wednesday. However, Bridenstine noted that NASA has the "right to intervene" if it sees something it disagrees with.

President Trump and Vice President Mike Pence are expected at Kennedy for the planned liftoff, but “our highest priority” will remain the astronauts' safety, according to Bridenstine.

Launched atop the Falcon 9 rocket, Crew Dragon will accelerate to approximately 17,000 mph, according to NASA, placing the capsule on course for the International Space Station. The duration of the astronauts’ stay on the International Space Station is yet to be determined.

Under normal circumstances, large crowds would have been expected to witness the historic launch but, citing concerns about the coronavirus pandemic, NASA has urged people to stay away. Hundreds of thousands of people flocked to the area near Kennedy Space Center for the last shuttle launch in July 2011, according to Spaceflight Now.

STS-135, the last space shuttle mission, launched from Kennedy Space Center on July 8, 2011. The space shuttle Atlantis carried four NASA astronauts on the mission to resupply the ISS, as well as an experiment for robotically refueling satellites in space.

Since then, the U.S. has relied on Russian Soyuz rockets launched from the Baikonur Cosmodrome in Kazakhstan to get astronauts into space. Russia charges the U.S. about $75 million to send an astronaut into space.

NASA recently agreed to pay Russian space agency Roscosmos $90 million for one final seat on one of its Soyuz rockets.

Fox News’ Kristin Fisher, Lauren Blanchard and The Associated Press contributed to this article. Follow James Rogers on Twitter @jamesjrogers. Get updates on this story from foxnews.com.