The 212-foot rocket, including an orange core stage and two white solid rocket boosters, had rested upon a ground structure called the mobile launcher, as it had during earlier tests. As the boosters ignited, the rocket lifted above an explosion of flames, and then it quickly cleared the launch tower and began its ascent through the atmosphere, an ombre orange streak blazing behind it. “Liftoff for Artemis 1,” proclaimed Derrol Nail, NASA’s livestream commentator. “We rise together, back to the moon and beyond.” After the two-minute mark, the SLS boosters finished burning through their propellant and fell away. About eight minutes after launch, the core stage rocket used up its fuel and separated too. That left the uncrewed Orion capsule still attached to the upper-stage rocket and the service module, provided by the European Space Agency, which supplies the spacecraft’s main propulsion and power. Orion continued on at over 16,000 miles per hour, and a few minutes later it deployed its solar arrays. If the mission goes according to plan, after about two hours, the capsule will separate from the SLS upper stage. As it drifts away, the upper stage will then disperse—in batches—10 small spacecraft known as CubeSats, sending them out to conduct mini missions around the moon, Mars, and a near-Earth asteroid. Meanwhile Orion will fly on, taking about 10 days to reach the moon, where it will spend a couple of weeks in what’s called a “distant retrograde orbit,” which balances the gravitational pull of the Earth and moon and doesn’t take much fuel to maintain. While circling the moon, it will take images of the Earth and its satellite—including one like the iconic “Earthrise” photo taken on the Apollo 8 mission—and collect space radiation data so that scientists can learn more about potential health risks for astronauts on extended trips beyond the Earth’s protective atmosphere. At the end of November, Orion will leave that orbit and cruise 40,000 miles beyond the moon—the farthest a spacecraft capable of carrying humans has ever traveled—before slingshotting back past it en route to Earth in early December. Its 26-day trip will end when it splashes down under parachutes into Pacific Ocean waters about 50 miles off the coast of San Diego, probably on December 11. Members of the Artemis mission team are ecstatic that this moment has arrived—and also anxious about the first major moonshot since the Apollo era. “I’m excited to kick off this Artemis mission series to go back to the moon and basically start a new era that will represent deeper space exploration, and on to Mars one day. I’m most excited to watch that rocket turn night into day tonight when it takes off. It’s going to be spectacular,” said NASA astronaut Christina Koch, speaking earlier Tuesday before the launch. There will be many scientific, economic, and other benefits to the Artemis program, she says, thanks to NASA’s international and commercial partnerships, and it will help inspire the next generation of space explorers. Today’s much-awaited launch was not the space agency’s first try. An attempt on August 29 was scrubbed when a liquid hydrogen leak was discovered with the third RS-25 engine. A second shot on September 3 was also called off due to a hydrogen leak—this time, it was larger. While NASA has plenty of experience with liquid hydrogen leaks during space shuttle launch attempts, the SLS is a new rocket, and it poses new challenges. The team next tried a “kinder, gentler loading approach” to tanking, using less pressure to push the propellant through the lines to the core-stage rocket, said Brad McCain, vice president of Jacobs Space Operations Group, the prime contractor for NASA’s Exploration Ground Systems, at a press conference in September. That worked during a tanking test on September 21. Still, the Artemis team’s would-be third launch attempt on September 27 was canceled when Hurricane Ian came rumbling in, forcing the team to roll back the rocket to the Vehicle Assembly Building for protection. Earlier this month, they trundled the rocket back to the pad in anticipation of a November 14 launch, just as Tropical Storm Nicole—soon to elevate to hurricane strength—grew on the horizon. NASA considered moving the rocket into shelter again, but that would have entailed some risks. Standing on the launchpad, parts of the rocket can tolerate sustained winds of up to 74 knots. But it’s more vulnerable if it’s on the crawler, the slow-moving machine that would be used to bring it indoors. In the end, there wasn’t enough time to deliver it to shelter. The team made the call to leave the rocket on the pad and push the launch date to November 16. Hurricane Nicole brought strong winds, including some around the 74-knot level. But NASA personnel assessed that storm damage to the SLS rocket and Orion capsule was minor. A very thin strip of caulk or insulation at the base of Orion’s protective nose cone had come loose, and they detected an electrical connection issue with a cable involved in the liquid hydrogen fueling of the rocket. While there’s a chance more of that caulk-like material could be stripped off during launch, the Artemis team deemed this a minimal risk, said Mike Sarafin, the Artemis mission manager, at a press conference on Monday. They decided to press ahead. Countdown procedures started up again at 1:24 am Eastern time Monday morning. The launch team and US Space Force meteorologists confirmed that the weather was 80 percent favorable, with no more hurricanes on the way. The team began gradually going through their checklist of 489 launch criteria. On Tuesday afternoon, they began filling the big orange fuel tank with more than 700,000 gallons of liquid hydrogen and liquid oxygen, supercooled to a frigid -423 and -297 degrees Fahrenheit. Finally, with 10 minutes left, launch director Charlie Blackwell-Thompson and the team made the call that they were “go” for launch. Speaking just a few minutes later, she told the team: “You have earned your place in history. You are part of a first. That doesn’t come along very often—once in a career, maybe. We are all part of something incredibly special: the first launch of Artemis. The first step in returning our country to the moon and on to Mars. What you have done today will inspire generations to come. So thank you for your resilience. The harder the climb, the better the view. We showed the Space Coast tonight what a beautiful view it is.” Artemis 1 should be considered a “test flight,” Parson says. That means even if some conditions aren’t ideal, they’re not likely to abort the mission mid-flight. At a NASA press conference in August, Sarafin underscored this point. “This is the first flight of a new rocket and new spacecraft, and it does carry inherent risk,” he said. “We have a ‘lean forward’ strategy to get our high-priority objective, which is to demonstrate the heat shield at reentry conditions [from the moon]. We would be ‘go’ on this flight for conditions that we’d normally be ‘no go’ on a crewed flight, in the interest of crew safety.” The Artemis team will be watching to see how Orion’s heat shield handles the scorching 5,000 degrees Fahrenheit during reentry through the atmosphere at about 25,000 miles per hour (or Mach 32, if you’re counting). The heat shield involves a special material called Avcoat, which is built into connected blocks at the bottom of Orion. As it heats up, parts of it slough off. Such heat shields have never been tested at the speeds a spacecraft returning from the moon will experience. The team will also be checking to see that the communication and navigation systems work well, supplemented by NASA’s Near Space Network of ground stations in Chile and South Africa. They’ll collect radiation data from sensors worn by the three mannequins riding onboard—including one dubbed “Commander Moonikin Campos”—plus data about the spacecraft’s trajectory and the temperature of the crew module. And they will be making sure that the three parachutes deploy properly, slowing the spacecraft to about 20 miles per hour. As Orion splashes down, NASA officials will work with a Navy recovery ship, including divers and team members on inflatable boats, so that they can safely and quickly retrieve the spacecraft, since there will be astronauts aboard next time. Orion’s return will set the stage for Artemis 2—and for even more far-flung trips to Mars. But it all depends on a first mission that demonstrates humankind is ready to take its next giant leap.