A SpaceX Falcon 9 rocket carrying the first privately developed spacecraft designed to ferry U.S. astronauts to orbit since NASA's shuttle was retired eight years ago is on track for blastoff on an unpiloted test flight early Saturday. The mission will help pave the way for the first commercial crew launch this summer.

With an instrumented astronaut test dummy nicknamed "Ripley" strapped into one of the Crew Dragon's four seats, liftoff from historic pad 39A at the Kennedy Space Center is targeted for 2:49 a.m. EST (GMT-5) Saturday. Forecasters are predicting an 80 percent chance of good weather.

"This is an absolutely critical first step as we move towards eventually returning crew launch capability back here to the U.S.," said Bill Gerstenmaier, director of space operations at NASA headquarters.

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How to watch the SpaceX Crew Dragon launch

On Saturday morning, SpaceX will launch its new spaceship on a critical test flight, marking the first time a commercially built and operated spaceship capable one day of carrying people will travel to the space station.

What: SpaceX Falcon 9 test flight of new Crew Dragon capsule

SpaceX Falcon 9 test flight of new Crew Dragon capsule When: Saturday, March 2, 2019

Saturday, March 2, 2019 Location: Launch Pad 39A at NASA's Kennedy Space Center in Florida

Launch Pad 39A at NASA's Kennedy Space Center in Florida Time: 2:49:03 a.m. EST (GMT-5)

2:49:03 a.m. EST (GMT-5) Online stream: CBSN live on your mobile device or in the video player above when the event starts.

Why is the SpaceX Crew Dragon launching at 2:49 a.m. EST?



The launching is timed to coincide with the moment Earth's rotation carries the pad into the plane of the International Space Station's orbit. Because the rocket does not have the power needed to steer into the station's orbit before or after that fleeting "in-plane" target, the Falcon 9 must take off on time or the flight will be delayed to March 5.

What is expected to happen after liftoff?

Assuming liftoff proceeds as scheduled early Saturday, the Crew Dragon spacecraft, carrying a few hundred pounds of supplies and the space-suited Ripley — named after the heroine in the sci-fi thriller "Alien" — will autonomously rendezvous with the International Space Station early Sunday.

Carrying out a series of tests along the way, the 13-ton capsule will approach from directly in front of the outpost, slowly moving in for docking at the lab's forward port around 6 a.m. as the two spacecraft orbit in tandem at nearly five miles per second.

Station astronaut Anne McClain, Canadian physician-astronaut David Saint-Jacques and cosmonaut Oleg Kononenko will be standing by inside the station, closely monitoring the automated approach, ready to open hatches and welcome the new addition to the lab.

An artist's impression of a SpaceX Crew Dragon spacecraft on final approach to the International Space Station. NASA

After a five-day stay, the spacecraft will undock next Friday, March 8, plunging back into the atmosphere for a parachute descent to splashdown in the Atlantic Ocean about 230 miles east of Cape Canaveral.

What is the purpose of the mission?

The long-awaited "Demo 1" mission is the most critical milestone yet in NASA's $8 billion effort to replace the shuttle with commercially developed ferry ships intended to end the agency's sole reliance on Russian Soyuz spacecraft to carry U.S. and partner astronauts to and from the space station.

"Great nations should be able to launch their own astronauts into space," NASA Administrator Jim Bridenstine told CBS News. "And with our investment in the international space station, it's as important for us as it is for anybody in the world."

The goal is prove it can safely dock and undock from the space station, re-enter the earth's atmosphere, and splash down off the Florida coast.

Engineering data collected during the flight will be used to shed light on a variety of known technical issues, ranging from the performance of the capsule's parachutes to temperature-related problems with its maneuvering thrusters and certification of redesigned high-pressure helium tanks, that must be addressed before the first astronauts fly this summer.

What is SpaceX?

SpaceX, founded in 2002 by entrepreneur Elon Musk, is a private company that designs, manufactures and launches advanced rockets and spacecraft. It is headquartered in Hawthorne, California.

Boeing is also in the commercial race to transport space station astronauts. Its first Starliner demo is targeted for the April-May timeframe, and the second, with a crew of three astronauts, is expected this fall.