SpaceX has launched NASA astronauts Doug Hurley and Bob Behnken on their historic Demo-2 mission to the International Space Station (ISS). The mission is the first time that astronauts have launched from American soil since the final Space Shuttle flight in 2011.

Hurley and Behnken blasted off from Kennedy Space Center’s historic launch pad 39A, which was also used for the Apollo and space shuttle programs, at 3:22 p.m. eastern today. An attempt on Wednesday was scrubbed due to weather conditions.

The launch is the first time a private company, rather than a national government, has sent astronauts into orbit.

There were concerns that bad weather would force today’s launch to be scrubbed, but the mission was able to proceed as planned. President Trump and Vice President Pence, who is chairman of the National Space Council, watched the launch from Kennedy Space Center.

Launched atop a SpaceX Falcon 9 rocket, Hurley and Behnken are traveling to the International Space Station in a Crew Dragon spacecraft built by the space company.

After a short journey into orbit, Crew Dragon began its 19-hour journey to the orbiting space lab.  Autonomous docking with the International Space Station is expected at 10:29 a.m. EDT tomorrow. The duration of the astronauts’ stay on the orbiting space lab is yet to be determined.

After separation, the Falcon 9 booster successfully returned to Earth, landing on a drone ship in the Atlantic.

“Today was just an amazing day,” NASA administrator Jim Bridenstine said shortly after the launch. “I can breathe a sigh of relief but I can also tell you that I’m not going to celebrate until Bob and Doug are home safely.”

Bridenstine said he was praying for the astronauts during the liftoff. “I have heard that rumble [of a rocket launch] before, but it’s a whole different feeling when you’ve got your own team on that rocket.”

Under normal circumstances, large crowds would have been expected to witness the historic launch but, citing concerns about the coronavirus pandemic, NASA urged people to stay away.

STS-135, the last space shuttle mission, launched from Kennedy Space Center on July 8, 2011. The space shuttle Atlantis carried four NASA astronauts on the mission to resupply the ISS, as well as an experiment for robotically refueling satellites in space.