SpaceX and NASA are about to once again send astronauts into space -- laying even more groundwork for what might become a regular thing ... and we'll be streaming the event live, with lift-off slated for 7:27 PM ET.

Elon Musk's shuttle program is embarking on yet another launch Sunday from the Kennedy Space Center in Florida -- where the SpaceX team is firing its famed Dragon capsule into orbit ... only this time, it's carrying a few more helmeted cadets on the mission.

Three American astronauts are signed up for this job -- NASA's Mike Hopkins, Shannon Walker and Victor Glover -- and so is a Japanese astronaut named Soichi Noguchi. Check out their suits, BTW ... super sleek compared to what they used to rock back in the day.

That's technology, baby!!! Also ... fashion.

The 4-person crew is heading to the International Space Station, where they'll conduct scientific research for NASA. This is the second time this year that SpaceX has sent up humans in partnership with NASA -- in May, they sent up astronauts Doug Hurly and Bob Behnken to the ISS for a couple months ... now, they're upping the manpower. It's the first SpaceX commercial crew trip to the ISS.

This latest mission is a huge milestone -- it marks a huge pivot away from our reliance on Russian space travel -- something the U.S. has been heavily reliant on in recent years.

The fact SpaceX is helping with these types of trips more regularly proves it's a leading company for a lot more travel in the near future -- which could open the door for space tourism. The possibilities are endless, really.

The launch is scheduled for 7:27 PM ET. Houston, we have lift-off ... hopefully.