Four astronauts blasted off from Florida on Wednesday on NASA's Artemis II mission, a high-stakes voyage around the moon that marks the United States’ boldest step yet toward returning humans to the lunar surface later this decade in a race with China.

NASA's Space Launch System (SLS) rocket, topped with its Orion crew capsule, roared to ‌life just before sunset at the agency's Kennedy Space Center in Cape Canaveral, Florida, carrying its debut crew - three US astronauts and a Canadian astronaut - into Earth orbit. The 32-story-tall space vehicle thundered into clear skies trailing a towering column of thick, white vapor.

NASA Administrator Jared Isaacman said the launch was an opening act for subsequent missions that would include construction of a moon base to support the "enduring presence we're trying to create on the surface."

If the mission proceeds as planned, the crew consisting of ​NASA astronauts Reid Wiseman, Victor Glover and Christina Koch, plus Canadian Space Agency astronaut Jeremy Hansen, will fly around the moon and back in their nearly 10-day expedition, putting the spacecraft through its paces ​while venturing deeper into space than humans have ever gone.