WATCH: SpaceX Falcon 9 rocket launches, carries first NASA astronauts into space in 9 years

We have liftoff.

For the first time in nine years, NASA astronauts are in space. Thanks to the boost from the SpaceX Falcon 9 rocket, the astronauts left Earth on Saturday afternoon.

At 3:22 p.m. ET., the SpaceX Falcon 9 rocket fired up its engines and blasted off from Cape Canaveral, Florida. NASA astronauts Bob Behnken and Doug Hurley were nestled in SpaceX's Crew Dragon capsule.

"Let's light this candle," Hurley said just before liftoff, an homage to Alan Shepard's quote from America's first human spaceflight in 1961. The SpaceX Falcon 9 rocket blasted off from the same launch pad used by Apollo astronauts that went to the moon a half-century ago.

After streaking through the sky at a speed of 17,000 mph, the first-stage Falcon 9 rocket broke away from the Crew Dragon capsule.

The Falcon 9 rocket, which is made by Elon Musk's SpaceX company, successfully touched down on a floating landing pad barge a few hundred miles off the Florida coast.

Then the second-stage rocket detached from the Crew Dragon capsule. The two astronauts are scheduled to float in orbit for the next 19 hours until they arrive at the International Space Station on Sunday, where they will stay for up to four months.

President Donald Trump and Vice President Mike Pence watched the historic launch at the Kennedy Space Center in Florida. This is the first-ever commercial manned mission to space.

The launch was originally scheduled for Wednesday afternoon, but it was canceled 17 minutes before liftoff because of inclement weather.