CAPE CANAVERAL, Fla. — The United States may have just taken a big step toward human spaceflight self-sufficiency with a first-of-its kind launch by SpaceX.

SpaceX's Crew Dragon capsule embarked on its first test mission to the International Space Station early this morning (March 2), launching atop a Falcon 9 rocket from NASA's Kennedy Space Center (KSC) here on the Space Coast.

Nobody is aboard Crew Dragon on this six-day flight, known as Demo-1, save a sensor-laden dummy astronaut named Ripley in an apparent nod to the sci-fi film "Alien." But if all goes according to plan with Demo-1 and a subsequent emergency-escape test, SpaceX will use the capsule to ferry two astronauts to the orbiting lab as early as this July.

That milestone will be huge: Astronauts haven't launched to orbit from American soil since NASA grounded its space shuttle fleet in July 2011. Ever since then, the nation has been dependent on Russian Soyuz rockets and spacecraft to ferry astronauts to and from the space station — at a cost, most recently, of about $80 million per seat.

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

SpaceX's first Crew Dragon launches atop a Falcon 9 rocket on the Demo-1 mission to the International Space Station from Pad 39A at Kennedy Space Center in Florida, March 2, 2019. (Image credit: collectSPACE.com

The two-stage Falcon 9 rocket lifted off this morning at 2:49 a.m. EST (0549 GMT), rising into the dark pre-dawn skies from KSC's historic Launch Pad 39A — the site of the last crewed American orbital spaceflight, the STS-135 mission of the space shuttle Atlantis.

"It's a truly exciting time," KSC Director Bob Cabana, a former astronaut who launched three times from 39A on shuttle missions, told reporters here yesterday (March 1). "I can't wait to see crews on top of that rocket."

About 10 minutes after liftoff, the Falcon 9's first stage came back to Earth, acing a touchdown on the SpaceX drone ship "Of Course I Still Love You," which was stationed off the Florida coast. One minute later, Crew Dragon separated from the rocket's second stage and began making its own way to the space station.

Related: SpaceX's Crew Dragon Demo-1 Test Flight in Pictures

A new kind of Dragon

SpaceX has been developing Crew Dragon under a $2.6 billion commercial-crew deal, which NASA awarded the company in 2014. Aerospace giant Boeing got a deal then, too: $4.2 billion to get its CST-100 Starliner capsule ready to fly.

At the time, NASA officials said they hoped to have one or both of these vehicles operational by the end of 2017.

Crew Dragon is an advanced, updated version of SpaceX's Dragon cargo vehicle , which has flown 16 robotic resupply missions to the International Space Station (ISS) for NASA to date. But there are some important differences.

For starters, Crew Dragon has windows, seats (up to seven can be installed), life-support and environmental-control systems, touch-screen displays, and an emergency-escape system. This latter feature, which is designed to get astronauts out of harm's way in case of a problem during launch, consists of eight SuperDraco thrusters built into the capsule's body.

Related: Take a Walk Through SpaceX's Crew Dragon Spaceship

In addition, Crew Dragon's solar panels are built into its trunk, and the capsule docks directly with the orbiting lab. The cargo version, by contrast, sports traditional deployable solar arrays, and it's grappled by the ISS's huge robotic arm.

Like the Falcon 9's first stage, cargo Dragon is reusable; it returns to Earth and makes parachute-aided splashdowns in the ocean. Indeed, numerous SpaceX ISS resupply missions have featured re-flown capsules and re-flown rockets .

The crew variant is designed to fly multiple times as well, but it won't do so — at least not on the initial NASA missions. SpaceX's current commercial-crew contract calls for the company to use new capsules and new rockets on each astronaut-ferrying flight.

Boeing's current contract allows reuse of Starliner, which will come down on dry land.

A quick trip

Demo-1 is a shakeout cruise. The mission is designed to put all of Crew Dragon's many systems through their paces in space to make sure the capsule is ready to take astronauts up and bring them down safely.

"We instrumented the crap out of this vehicle. It's got data, sensors everywhere," Kathy Lueders, manager for NASA's Commercial Crew Program, said during a pre-launch news conference here at KSC Thursday (Feb. 28).

Some of those sensors were fitted to the "anthropomorphic test device" Ripley, which was named after Ellen Ripley from the "Alien" movie franchise.

"The goal is to get an idea of how humans would feel in her place, basically," SpaceX Vice President of Build and Flight Reliability Hans Koenigsmann said Thursday. "I don't expect, actually, a lot of surprises there, but it's better to verify — make sure that it's safe and everything's comfortable for our astronauts going on the next flight of the capsule."

If all goes according to plan, Crew Dragon will arrive at the ISS tomorrow morning (March 3), docking autonomously at about 6 a.m. EST (1100 GMT). The capsule will deliver about 400 lbs. (180 kilograms) of supplies to crewmembers aboard the orbiting lab — but no scientific experiments.

"We want to focus on the test objectives," David Brady, assistant program scientist for the ISS, told reporters here yesterday. Having scientific gear aboard could compromise that focus, he explained.

Crew Dragon will probably end up toting about 220 lbs. (100 kg) of experiments on fully operational missions, he added. That may not seem like a lot, but a lot isn't needed; cargo Dragon and other freighters will continue to carry the bulk of the ISS's science load, Brady said.

Demo-1 will come to an end on Friday (March 8). Crew Dragon is scheduled to depart the orbiting lab at around 2:30 a.m. EST (0730 GMT) that day and splash down in the Atlantic Ocean, not far from the Florida coast, about 6 hours later. (Cargo Dragons come down in the Pacific . But SpaceX wants to start processing landed Crew Dragons at the company's Florida facilities quickly, which explains the shift in splashdown sites, Koenigsmann said.)

The next steps

This same Crew Dragon capsule is scheduled to fly again soon, to give those SuperDracos some action. SpaceX's uncrewed "high-altitude abort test" is officially planned for June , but company founder and CEO Elon Musk recently said that it could occur as early as April, if all goes well with Demo-1.

A successful abort test would then pave the way for Demo-2 in July. This historic test flight will send two NASA astronauts — Bob Behnken and Doug Hurley, each of whom has two shuttle missions under his belt — to the ISS.

Behnken and Hurley came down to KSC for today's launch, as did Victor Glover and Mike Hopkins, who will fly on the first operational Crew Dragon mission. The NASA astronauts aim to learn as much as they can about the capsule before they fly it.

"I can't begin to explain to you how exciting it is for a test pilot to see the first flight of a vehicle," Hurley said during a press event here yesterday.

Fully operational, contracted Crew Dragon flights will start sometime after that. Those missions will tote four astronauts to and from the ISS — one more than the maximum carried by Russia's Soyuz spacecraft . The extra person will make a huge difference, increasing the time ISS crewmembers can devote to science experiments; they currently do 40 to 50 hours per week, and that could rise to 80 to 90 hours, Brady said.

Starliner will enable similar gains, as it will also carry four people per trip (though, like Crew Dragon, it can accommodate seven). And Boeing's capsule could get off the ground quite soon as well. Its first test flight, an uncrewed mission to the ISS like Demo-1, is scheduled to take place sometime in April or later.

Starliner will perform an abort test of its own no earlier than May, and its first crewed demonstration flight to the ISS could come in August.

These private vehicles' operational debuts will end NASA's reliance on the Soyuz but not the agency's use of the Russian vehicle. At least for the near term, American astronauts will continue to fly on the Soyuz, and each contracted Crew Dragon and Starliner flight will include one cosmonaut, NASA officials said.

"The Russians have been really great partners," Cabana said. And, he added, "we want to have interoperability. We want to have redundancy, so if there's a problem with one vehicle, we can fly another."

That private spacecraft will provide this redundancy is especially exciting for NASA, Cabana said.

"It's time to turn low-Earth-orbit operations over to the commercial sector," he said. "NASA's been going back to low Earth orbit for over 50 years; we know how to do that. We're focused on exploring now — establishing the Gateway around the moon , going back to the lunar surface and going on to Mars."