SpaceX plans to launch a new spaceship for NASA astronauts, called Crew Dragon, early Saturday morning at 2:49 a.m. ET.

launch a new spaceship for NASA astronauts, called Crew Dragon, early Saturday morning at 2:49 a.m. ET. The experimental launch won't carry any people, just cargo and a dummy named Ripley. However, NASA says it's "a very critical mission" to proving the vehicle is safe to fly.

Crew Dragon will rocket toward the International Space Station, arrive at the orbiting laboratory early Sunday morning, then depart and land in the Atlantic Ocean a few days later.

If this dress rehearsal for NASA's $8 billion Commercial Crew Program goes well, Elon Musk's rocket company may fly its first astronauts as soon as July.

Commercial Crew Program goes well, Elon Musk's rocket company may fly its first astronauts as soon as July. Here's what to expect and when from the demonstration mission, which is called SpaceX Demo-1.

CAPE CANAVERAL, Florida — SpaceX is about to launch one of the most critical space missions in the company's 17-year history.

After years of delays, NASA and its partners have given SpaceX a "go" to launch its new spaceship for astronauts, called Crew Dragon (or Dragon 2), for the first time ever.

Elon Musk's rocket company seeks to show that it can safely fly astronauts in its commercial spaceships. NASA, for its part, describes the mission as a "critical step" in resurrecting the ability to launch astronauts from US soil in American spaceships.

Crew Dragon is scheduled to launch atop a Falcon 9 rocket on Saturday at 2:49 a.m. ET from Kennedy Space Center in Cape Canaveral, Florida. No people will fly inside the spaceship for this first demonstration — just cargo and sensor-laden dummy.

"Her name is Ripley," Hans Koenigsmann, SpaceX's vice president for build and flight reliability, revealed on Thursday. The dummy's name is an homage to Ellen Ripley, the lead character in the film "Alien" played by Sigourney Weaver.

The mission is called SpaceX Demo-1 in formal circles, and if all goes well, the spaceship will travel to the International Space Station, dock with the $150 billion laboratory, then return to Earth a few days later.

Read more: SpaceX will launch its Crew Dragon spaceship into orbit for the first time ever on Saturday. Here's how to watch live.

"Demo-1 is a flight test, it absolutely is, although we view it also as a real mission, a very critical mission," Kirk Shireman, who manages the space station program at NASA's Johnson Space Center, said during a press briefing about the upcoming launch. "The ISS still has three people on board, and so this vehicle coming up to the ISS for the first time has to work. It has to work."

Here's what to expect and when from the first experimental, orbital-class flight of SpaceX's Crew Dragon space capsule.