The crew led by Commander Hopkins, an Air Force colonel, includes physicist Shannon Walker and navy Commander and first time astronaut Victor Glover, who will be the first Black man to spend an extended period of up to six months aboard the space station.
SpaceX's human launch program was developed under the Commercial Crew program, which saw NASA select two private companies to build astronaut launch systems for carrying astronauts to the ISS from US soil.
The Crew Dragon spacecraft lifted off from Launch Complex 39A at 7:27 p.m. ET Sunday. For the previous flight involving a Crew Dragon (Demo-2), astronauts Behnken and Hurley named their spacecraft Endeavour after the Space Shuttle that had taken both astronauts on their maiden flight to space.
While SpaceX made its second successful flight, the Boeing program hit a roadblock after a failed test of its uncrewed Starliner past year.
NASA has been relying on Russian Soyuz rockets to get its astronauts to the space station.
Four astronauts are scheduled to head to the International Space Station aboard a SpaceX Dragon capsule.
NASA Administrator Jim Bridenstine said the launch was a "great day" for both the U.S. and Japan.
Crew commander Mike Hopkins certainly enjoyed the launch, radioing mission control, "Well done, that was one heck of a ride".
Jeremih In Intensive Care Unit Fighting COVID-19
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Eastern time (0027 GMT on Monday) from NASA's Kennedy Space Center in Cape Canaveral, Florida. During an internship with SpaceX, she helped create ground support equipment for the Falcon 9 vehicle, used in Sunday's launch.
It is the first of six crewed missions that NASA and SpaceX will operate as part of the Commercial Crew Program, whose objective is to make access to space easier in terms of its cost, so that cargo and crew can be easily transported to and from the ISS, enabling greater scientific research.
This is the first of what NASA calls "operational" flights of the Crew Dragon.
The launch marks the U.S.'s return to manned orbital launches, nearly 10 years after the Space Shuttle program ended.
In the intervening years, United States astronauts have had to hitch rides into orbit aboard Russia's Soyuz spacecraft.
In 1961, cosmonaut Yuri Gagarin carried a small doll with him on his Vostok 1 mission to watch it float in zero gravity.
"Crew-1" is the first of three scheduled Dragon flights over the course of 2020 and 2021, according to SpaceX.
The four astronauts - three from the U.S. and one from Japan - are headed for the International Space Station (ISS).