3:10 PM PT -- The two NASA astronauts, Robert Behnken and Douglas Hurley, have finally disembarked the Dragon capsule ... and they're already looking forward to Saturday's rescheduled launch.
1:23 PM PT -- Elon is going to have to wait a little longer for his company to make history ... SpaceX says Wednesday's launch is OFF due to "unfavorable weather in the flight path."
SpaceX pulled the plug minutes before the rocket carrying astronauts to the ISS was about to blastoff from Florida ... and the next launch is tentatively scheduled for Saturday at 3:22 PM ET.
10:59 AM PT -- The astronauts are already loaded into the capsule and are going through safety protocols. As of now, all systems are go!
Elon Muskis looking to make more space history ... SpaceX is attempting to launch 2 NASA astronauts to the International Space Station ... and TMZ will be live streaming the mission.
Dubbed Demo-2, the mission marks the first time ever a commercial aerospace company is sending humans into Earth's orbit. The milestone is a decade in the making, as human spaceflight finally returns to American soil.
The launch of SpaceX's Crew Dragon is set for 4:33 PM ET from the Kennedy Space Center in Florida ... and the Falcon 9 rocket carrying the capsule is taking off from the historic Pad 39A, which famously launched Apollo 11 way back in 1969, the first moon landing.
SpaceX and NASA are streaming the launch from takeoff all the way until Crew Dragon docks with the ISS, and it should take the capsule about 19 hours to travel from Florida to the space station.
The two veteran astronauts aboard the Dragon spacecraft are 49-year-old Robert Behnken and 53-year-old Douglas Hurley.
NASA says it wants to keep the astronauts on the ISS until another Crew Dragon capsule is ready to send more humans on SpaceX's next mission. Robert and Douglas say they're expecting to spend 1 to 3 months in space before returning home in Crew Dragon, which will land in the Atlantic Ocean.
SpaceX's Falcon 9 rocket will launch the Crew Dragon into Earth's upper atmosphere, where the capsule will separate and use its own thrusters to make its way to the ISS. The capsule is fully autonomous, so the astronauts won't have much to do, unless something crazy happens. The rocket, meanwhile, should land on a drone ship after launch.
SpaceX has a $2.6 BILLION contract with NASA ... and the launch marks the first time the United States is sending its own astronauts into space since 2011, when the Space Shuttle Program ended.
Oh, and the capsule has a toilet, which could come in handy during the 19-hour ride.