CAPE CANAVERAL, Fla. — It's almost "go" time for SpaceX's first spaceship built for NASA astronauts.

SpaceX's first Crew Dragon spacecraft is poised for a historic test flight Saturday (March 2), when it's scheduled to soar into orbit from NASA's Kennedy Space Center here atop a Falcon 9 rocket. Liftoff is set for 2:48 a.m. EST (0748 GMT).

There won't be a crew aboard this Crew Dragon test flight, but the mission — called Demo-1 — is carrying the hopes of SpaceX and NASA to once again be able to launch their astronauts on American rockets from U.S. soil. It's also carrying a spacesuit-clad test dummy nicknamed Ripley and 400 lbs. (181 kilograms) of supplies.

Related: SpaceX Dragon Crew Demo-1 Flight: Full Coverage

SpaceX's first Crew Dragon spacecraft and its Falcon 9 rocket roll out Launch Pad 39A of NASA's Kennedy Space Center on Feb. 28, 2019 in Cape Canaveral, Florida. Launch is set for March 2. (Image credit: Joel Kowsky/NASA)

The mood among NASA's team is palpable.

"People are just ... we're ready," Joel Montalbano, NASA's deputy manager for the International Space Station program, told reporters in a prelaunch conference today (Feb. 28). "We're looking forward to the launch this weekend."

If all goes according to plan, Crew Dragon will launch toward the International Space Station before dawn on Saturday and arrive at the orbiting laboratory in the wee hours of Sunday (March 3). That's when the spacecraft will dock itself at the station in a first for SpaceX, whose Dragon cargo ships have historically been captured by astronauts using a robotic arm.

After five days linked to the station, Crew Dragon will undock and return to Earth on March 8, splashing down in the Atlantic Ocean just off the coast of Florida. A SpaceX recovery ship will retrieve the capsule and ferry it back in to port.

"The task ahead of us is really historic," Hans Koenigsmann, SpaceX's vice president of build and flight reusability, in the news conference.

Related: How to Watch SpaceX's 1st Crew Dragon Test Flight Live

There's a lot riding on this mission. For SpaceX, it's the start of commercial crew missions for NASA under a $2.6 billion deal struck with the agency back in 2014. The Hawthorne, California-based company has been flying robotic Dragon cargo ships to the station for NASA since 2012, but Crew Dragon is a new ship specifically built to carry astronauts.

In fact, SpaceX's billionaire CEO Elon Musk founded the company in 2002 with the goal of flying people to space, and ultimately to Mars.

"We've been working and developing rockets and spacecraft for, I guess, close to 17 years by now," Koenigsmann said. "And for the team, this is the culmination of what we were founded for. This is what we wanted to do."

For NASA, the stakes may be more profound. The space agency has not been able to launch astronauts from U.S. soil since 2011, when its space shuttle fleet retired after 30 years of service and 135 missions. Since then, NASA has been dependent on Russia to fly crews to the station on Soyuz spacecraft.

"This is big day for us, obviously," NASA's Commercial Crew program manger Kathy Leuders said. "We're getting ready to go fly our first uncrewed mission with what will be the crewed design of the SpaceX Dragon."

Related: Take a Walk Through SpaceX's Crew Dragon

While SpaceX has been flying automated Dragon vehicles to the space station for years, the Crew Dragon carries some key differences and NASA wants to be sure they work as planned. First, it has a dedicated life support system to keep four-person crews alive on trips to and from the station.

Crew Dragon also has eight SuperDraco rocket engines to pull the spacecraft to safety in the event of launch emergency. Its solar arrays are built into the skin of the spacecraft's trunk, which sports a set of sleek fins.

NASA wants to know what future astronauts will feel when they fly on Crew Dragon. That's why it's carrying Ripley, an anthropomorphic test dummy clad in a SpaceX spacesuit and filled with sensors to measure forces, radiation and other aspects of a Crew Dragon trip.

"We instrumented the crap out of this vehicle, it's got data, sensors everywhere," Lueders said. "Actually having a re-entry, with Ripley in the seat, in the position, is critical."

If all goes well, SpaceX's Crew Dragon test flight will kick off a wave of demonstration flights by the Hawthorne, California-based company, as well as by one of its biggest competitors: Boeing.

Like SpaceX, Boeing won a NASA contract in 2014 to fly astronauts to the space station. That deal, worth $4.2 billion, calls for Boeing to launch astronauts on its CST-100 Starliner spacecraft using Atlas V rockets. Boeing's first uncrewed Starliner test flight is scheduled for April.

If the uncrewed test flights go well for SpaceX and Boeing, both companies will follow up with in-flight abort system tests in the spring. SpaceX hopes to launch its first crew, NASA astronauts Bob Behnken and Doug Hurley, in July. Boeing aims to launch its first crew a month later.

But first, SpaceX has to ace its Crew Dragon debut. The brand-new Falcon 9 rocket carrying the spacecraft currently stands atop the historic Launch Pad 39A here at the Kennedy Space Center — the same one used by NASA Apollo and shuttle missions.

"Everything is in top condition. Everything is freshly painted," Koenigsmann said. "I'm pretty sure we're going to see a great launch and a great mission. I'm pretty optimistic."

Editor's note: You can watch the Crew Dragon Demo-1 test launch live on Space.com here Saturday, March 2, beginning at 2 a.m. EST.