Today at 4:33 ET — but only if the weather in Florida cooperates — two NASA astronauts plan to strap themselves into a capsule atop a SpaceX rocket and travel to space, Nature reports.
“If the launch succeeds, it will mark a number of firsts in human spaceflight. It will be the first time a private company has flown humans to orbit, and the first time astronauts have launched from US soil since NASA retired the Space Shuttle in 2011. Perhaps most significantly, it is the first time in 17 years that anyone has launched a new type of spaceship to carry humans to Earth orbit.”
Update: The launch was scrubbed until May 30.