SpaceX will take another crack at its first crewed mission today (May 30), weather permitting, and you can watch the historic liftoff live.

A SpaceX Falcon 9 rocket is scheduled to launch the Crew Dragon capsule today at 3:22 p.m. EDT (1922 GMT) from Pad 39A at NASA's Kennedy Space Center in Florida, kicking off the crucial Demo-2 test flight to the International Space Station (ISS). You can watch the launch and lots of pregame festivities live here at Space.com, courtesy of NASA TV; coverage begins at 11 a.m. EDT (1500 GMT).

SpaceX first tried to launch Demo-2 on Wednesday (May 27) but had to scrub the attempt about 20 minutes before liftoff due to bad weather. There's a 50% chance that Mother Nature will cooperate today, according to the latest forecasts. 

"We are moving forward with launch today," NASA Administrator Jim Bridenstine said in a Twitter update today. 

There's no leeway in that launch window, by the way. If Demo-2 cannot get off the ground at 3:22 p.m., the mission team will have to start working toward the next available opportunity, which comes Sunday (May 31) at 3:00 p.m. (1900 GMT).

NASA astronauts Bob Behnken and Doug Hurley are riding on Demo-2, which will be the first orbital crewed mission to launch from the United States since NASA's space shuttle fleet was grounded in July 2011. Since then, Russian Soyuz spacecraft have been the only ride to and from orbit for American astronauts, and everyone else as well.

But that's about to change. If Demo-2 goes well, SpaceX will be clear to begin flying operational crewed missions to and from the ISS with Crew Dragon and the Falcon 9. The company is committed to fly six such missions under a $2.6 billion deal it signed with NASA in 2014.

Boeing signed a similar, $4.2 billion contract at the same time, which it will fulfill using a capsule called CST-100 Starliner. But Boeing isn't yet ready to launch astronauts; Starliner must first refly an uncrewed test mission to the ISS, after failing to meet up with the orbiting lab as planned during a December 2019 attempt. 

Crew Dragon notched that milestone in March 2019, during an eight-day uncrewed mission to the ISS called Demo-1.