With a dash of launch-pad heroics and 8.8 million pounds (4 million kg) of thrust, NASA's colossal new rocket soared into space for the first time early on Wednesday, sending a next-generation capsule on a crewless voyage around the moon and back 50 years after the final Apollo lunar mission.
The US space agency's much-delayed and highly anticipated launch from Florida kicked off Apollo's successor program, Artemis, aimed at returning astronauts to the lunar surface this decade and establishing a sustainable base there as a stepping stone to future human exploration of Mars.
The 32-story-tall Space Launch System (SLS) rocket blasted off from NASA's Kennedy Space Centre at 1:47 am EST (0647 GMT), piercing the blackness over Cape Canaveral with a reddish-orange tail of fire as crowds of spectators cheered and screamed. About 90 minutes later, the rocket's upper stage propelled the Orion capsule out of Earth orbit and on its trajectory to the moon, NASA said.
The three-week Artemis I mission entails a 25-day Orion flight bringing the capsule to within about 60 miles (97 km) of the lunar surface before flying about 40,000 miles (64,400 km) beyond the moon and looping back to Earth. The capsule is expected to splash down at sea on Dec 11.
"Today, we got to witness the world's most powerful rocket take the Earth by its edges and shake the wicked out of it. And it was quite a sight," Artemis mission manager Mike Sarafin told a post-launch NASA briefing, using words from biblical scripture.
Aside from some minor instrument issues, "this system is performing exactly as we intended it to," Sarafin said.
Liftoff came on the third try at launching the multibillion-dollar rocket - Aug 29 and Sept 3 attempts were aborted - after 10 weeks beset by technical mishaps, back-to-back hurricanes and two excursions trundling the spacecraft out of its hangar to the launch pad.
LAUNCH PAD HEROICS
Wednesday's launch was not without its own drama. About four hours before blastoff, crews had to deal with a flurry of issues including a leaky fuel valve. Quick work by a special "red team" of technicians, who tightened down a loose connection on the launch pad well inside the "blast zone" demarcated around a nearly fully fueled rocket, was credited with saving the launch.
The mission marks the first flight of the combined SLS rocket and the Orion capsule together, built by Boeing Co and Lockheed Martin Corp, respectively, under contract with NASA.
It signals an ambitious change in direction for NASA's post-Apollo human spaceflight program after decades focused on low-Earth orbit with space shuttles and the International Space Station. (See graphic)
Named for the ancient Greek goddess of the hunt - and Apollo's twin sister - Artemis aims to return astronauts to the moon's surface as early as 2025.
To date, only 12 people have ever walked on the moon, all of them NASA astronauts, during six Apollo missions running from 1969 to 1972 - a Cold War-era feat born of the US-Soviet space race. More science-driven than Apollo, the Artemis program has far greater horizons and has enlisted commercial partners such as Elon Musk's SpaceX and the space agencies of Europe, Canada and Japan.
Although no people were aboard, Orion carried a simulated crew of three mannequins fitted with sensors to measure radiation levels and other stresses that astronauts would experience.
'YOU COULD FEEL IT'
The thunder of the thrust produced by the rocket's four main R-25 engines and its twin solid-rocket boosters shook the Kennedy complex.
"It was just incredible to see. It was so bright, so loud, you could feel it," said NASA astronaut Jessica Meir, an Artemis crew candidate.
Orion will have some company around the moon. A tiny satellite, CAPSTONE, reached lunar orbit on Sunday to try out a complex gravitational parking position that may be suitable for a future lunar space station called Gateway, under development for the Artemis program.
Artemis I is intended primarily to put the SLS-Orion vehicle through its paces, pushing its design limits to prove its safety and reliability to fly astronauts.
If the mission succeeds, a crewed Artemis II flight around the moon and back could come as early as 2024, followed within a few years by the program's first lunar landing of astronauts, one of them a woman, with Artemis III. Sending astronauts to Mars is expected to take at least another decade and a half to achieve.
The SLS represents the biggest new vertical launch system NASA has built since the Apollo era's Saturn V.
A top objective is to test the durability of Orion's heat shield as it re-enters Earth's atmosphere at 24,500 miles (39,400 km) per hour - much faster than re-entries from the space station.
The spacecraft also is set to release 10 miniaturized science satellites including one designed to map ice deposits on the moon's south pole, where Artemis seeks to eventually land astronauts.
More than a decade in development with years of delays and budget overruns, the SLS-Orion spacecraft has cost NASA least $37 billion, with total Artemis spending projected to reach $93 billion by 2025. NASA has said the program has generated tens of thousands of jobs and billions of dollars in commerce.