In a jaw-dropping spectacle, the 322-foot-tall, the most powerful ever built for NASA, finally blasted off Wednesday with an eruption of white-hot fire and an earth-shaking roar, boosting an uncrewed Orion capsule on a flight to the moon to open a new era in American space flight.
After multiple delays due to repeated hydrogen fuel leaks, ground system glitches, two hurricanes and back-to-back launch slips, the Space Launch System rocket’s four main engines finally roared to life at 1:47 a.m. EST, followed a few seconds later by ignition of two extended strap-on solid-fuel boosters.
At that instant, four explosive bolts at the base of each booster detonated to free the SLS from its launch stand and the 5.7-million pound rocket leaped away from pad 39B, propelled skyward by 8.8 million pounds of thrust, hitting 70 mph — straight up — in about 7 seconds.
The launch came about 45 minutes later than planned after engineers noticed an intermittent leak around a valve used to replenish hydrogen in the core stage and trouble with data relay from a Space Force Eastern Range tracking radar. Both issues were resolved, but mission managers had to order a delay while the team made up for lost time.
Thrilling thousands of viewers, including spaceport workers, area residents and tourists who stayed up for the historic launching, the SLS briefly turned night into day as it consumed its propellants, lost weight and rapidly accelerated along a slightly northeasterly trajectory.
The initial moments of the climb-out occurred in eerie silence as it took several seconds for a wall of sound to race across the 4.2 miles separating the launch pad from the nearest observers, arriving with a defining roar that shook the ground like an earthquake in a visceral reminder of the rocket’s enormous power.
The SLS was expected to be moving faster than sound less that one minute after liftoff. One minute after that, the two strap-on boosters, which provide the lion’s share of the liftoff thrust, burned out and fell away, leaving the four engines powering the core stage to continue the climb to space.
Eight minutes after liftoff, the SLS second stage and the attached Orion capsule separated from the core stage in an initial elliptical orbit tilted 34 degrees to the equator. The core stage, meanwhile, was left to fall back into the atmosphere to break up over an unpopulated stretch of the Indian Ocean.
Two critical engine “burns” are then required to keep the spacecraft on track: one to raise the low point of the initial orbit, and a second to propel the Orion out of Earth’s gravitational clutch and onward to the moon. The 18-minute-long trans-lunar injection, or TLI, burn was expected about 90 minutes after launch.
The Orion capsule was expected to separate from the Interim Cryogenic Propulsion Stage, or ICPS, about two hours after launch, voyaging on to the moon for a 60-mile-high flyby Monday, using lunar gravity to fling it into a distant orbit that will carry it farther from Earth than any human-rated spacecraft.
The Artemis 1 mission is the first in a series of SLS/Orion flights. Future missions are intended to establish a sustained presence on and around the moon with a lunar space station called Gateway and periodicwhere ice deposits may be reachable in cold, permanently shadowed craters.
Future astronauts may be able to “mine” that ice if it’s present and accessible, converting it into air, water and even rocket fuel to vastly reduce the cost of deep space exploration.
More generally, Artemis astronauts will carry out extended exploration and research to learn more about the moon’s origin and evolution and test the hardware and procedures that will be necessary before eventually sending astronauts to Mars.
The goal of the Artemis 1 mission is to put the Orion spacecraft through its paces, testing its solar power, propulsion, navigation and life support systems before a return to Earth December 11 and a 25,000-mph plunge back into the atmosphere that will subject its protective heat shield to a hellish 5,000 degrees.
Testing the heat shield and confirming it can protect future astronauts returning from deep space is the No. 1 priority of the Artemis 1 mission.
If all goes well with Artemis 1, NASA plans to launch a second SLS rocket in late 2024 to boost four astronauts on a looping free-return trajectory around the moon. Then it aims to land the first woman and the next man on the lunar surface near the south pole in the Artemis 3 mission.
That flight, targeted for launch in the 2025-26 timeframe, depends on the readiness of new spacesuits for NASA’s moonwalkers and a lander being built by SpaceX that’s based on the design of the company’s reusable Starship rocket.
SpaceX is working on the lander under a $2.9 billion contract with NASA, but the company has provided little in the way of details or updates and it’s not yet known when NASA and the California rocket builder will actually be ready for the Artemis 3 lunar landing mission.
But if the Artemis 1 test flight is successful, NASA can check off its requirement for a super-heavy-lift rocket to get the initial missions off the ground and on to the moon.