For the first time in nearly nine years, Americans will be launched into space from U.S. soil when a SpaceX rocket lifts off from the Kennedy Space Center in Cape Canaveral, Fla.
Two astronauts will be on board the first crewed mission for a commercial spacecraft.
Here is everything you need to know about Saturday's launch.
What is SpaceX?
Space X is short for Space Exploration Technologies. It was founded by Tesla CEO Elon Musk in 2002. Unlike the government-run NASA, SpaceX is a private company.
What time is liftoff?
3:22 p.m. EDT, Saturday, May 30. The launch was scheduled for Wednesday, but it was scrubbed due to weather.
The next backup launch opportunity would be Sunday, May 31, at 3:00 p.m. EDT.
What is purpose of the mission?
It's called the Demo-2 mission. It's the final flight test for Space X to determine the full operational capabilities of its spacecraft, to successfully send humans into space and to dock with the International Space Station.
What is the spacecraft?
The rocket used on this mission is called the Falcon 9. The astronauts will be riding in the Crew Dragon capsule atop the rocket.
The Falcon 9 is a two-stage rocket. What makes it unique is that the first stage is capable of returning to Earth and landing vertically. This allows it to be used again for future flights.
The Crew Dragon for this mission is designed to spend up to 110 days in space. The operational version will be capable of 210 days in orbit.
Who are the astronauts?
While its SpaceX that's running the mission, NASA is providing the astronauts.
Robert L. Behnken is the joint operations commander for the mission. He was a colonel in the U.S. Air Force. He is a veteran of two space shuttle flights, having spent more than 29 days in space.
Douglas Hurley will be the spacecraft commander. He was a colonel in the U.S. Marine Corps. He is also a space veteran. He piloted the space shuttle twice, including the program's final mission.
What happens after liftoff?
The Crew Dragon will be pushed into orbit at 17,000 mph. At approximately 11:30 a.m. EDT on Thursday, May 28, the crew will rendezvous with the ISS. Docking is done automatically, but the crew can take over if they need to.
How long will they be in space?
It could be anywhere from one to four months, We don't know (yet). Behnken and Hurley will become part of the ISS Expedition 39 crew. They will conduct tests on the Crew Dragon and do research with the rest of the ISS crew. The duration of the mission will be determined based on the readiness of the next commercial vehicle launch.
How does the Crew Dragon land?
Like in the good old days of NASA's Mercury, Gemini and Apollo programs, the Crew Dragon will deploy parachutes after re-entry and splashdown off Florida's Atlantic coast.
Is this the first time SpaceX has launched something?
Far from it. It has performed several remotely-piloted missions to the ISS to test docking capabilities and deliver supplies. It has also delivered satellites into orbit.
So why is this historic?
This will be the first time that Americans will be launched into space from U.S. soil since July 2011. That's when the Space Shuttle program ended. For the last nine years, Astronauts have had to hitch a ride with the Russians.
It will also be the first time that a private venture will take humans into Earth orbit. Only the governments of the U.S., Russia and China have done it before now. It opens one more door toward eventually making space accessible to civilians.
For NASA, it's a significant step toward the Artemis program which will return humans to the Moon in the next few years and, finally, to Mars.
Did you know SpaceX launched a car?
Did you know there's a Tesla Roadster orbiting our sun right now? Musk launched it in 2018 aboard SpaceX's more powerful rocket, the Falcon Heavy. The car comes complete with a dummy astronaut wearing a SpaceX spacesuit. A camera on board showed us the vehicle tumbling around with Earth behind it. The roadster is in an elliptical orbit which will have it cross the paths of the Earth and Mars. Barring an unforeseen collision with an asteroid, it could orbit for millions of years.