NASA’s Artemis I mission successfully returns from the moon

50 years ago today, during NASA’s Apollo 17 mission, humans landed on the lunar surface for the last time. And now, after a journey of 1.4 million miles, NASA’s Orion spacecraft is safely back on Earth — marking the conclusion of the agency’s Artemis I mission and the first step in returning humans to the Moon.

“Artemis paves the way for living and working in space, in a hostile environment — to invent, create, and eventually go to Mars with humans,” NASA Administrator Bill Nelson told reporters nearly two weeks before the splashdown.

Launched in the early hours of November 16, Artemis I is the first flight test of NASA’s massive Space Launch System (SLS) rocket and the first lunar foray of the agency’s manned Orion spacecraft. During its 26-day mission, Orion traced a record-breaking path around the moon, winding its way to within 80 miles of the lunar surface — and flying furthest beyond the moon to a point about 270,000 miles from Earth. NASA executives put the spacecraft through its paces, challenging it to remain operational in the hostile environment of space for much longer than a typical crewed mission would take. They tested its propulsion, communications, life support, and navigation systems — and found no major problems.

“It was an incredible success and, as far as we know, the problems encountered were really minor,” says Teasel Muir-Harmony, space historian and curator of the Apollo Collection at the National Air and Space Museum. “With a new launch vehicle and a really complicated mission, it’s exciting to see it work so well.”

The most important – and most dangerous – test took place today, when Orion left space and returned to Earth at high speed. Traveling at about 25,000 miles per hour, the spacecraft performed what is known as a skip reentry, in which it briefly dipped in and out of the outer reaches of the atmosphere to slow down before making a second, final jump. When it next touched Earth’s air, Orion dove all the way through, rather than skimming the atmosphere like a leaping rock. When the spacecraft crashed, atmospheric friction heated its exterior to more than 5,000 degrees Fahrenheit, or about half the temperature of the Sun’s surface.

“You’re basically going through a blowtorch,” says Daniel Dumbacher, who oversaw initial development of the SLS while at NASA and now serves as executive director of the American Institute of Aeronautics and Astronautics. “We will never be comfortable and complacent about reentry. Reentry is a high-risk, high-energy event [maneuver]; They want to make sure you’re doing it right.”

To survive that fall without burning up, the spacecraft’s heat shield had to function perfectly—and it did. Next came the drogue and main parachutes on board, the latter of which deployed when the capsule was 5,300 feet above the Pacific Ocean, slowing its speed to just 20 miles per hour.

At 12:40 p.m. ET, Orion was bobbing safely like an oversized, multi-billion dollar cork among the whitecaps off the coast of Guadalupe Island, awaiting recovery by a contingent of NASA and US Navy personnel.

A smooth shakedown cruise

Just after 1:45 am ET on November 16, NASA’s orange SLS rocket roared to life and soared into the sky, illuminating Florida’s space coast in an artificial dawn. The launch was a triumph: this was the largest rocket humans have ever sent into space and the first time a manned spacecraft has visited near the moon in half a century. These milestones came after years of development and testing delays, during which costs skyrocketed. And they followed frustrating months of inactivity on the launch pad after leaks during refueling destroyed previous flight attempts and swept through several hurricanes, one of which lashed the SLS-and-Orion “stack” with torrential rain and 100-mph storms.

But after that bumpy start, the road smoothed out. The SLS placed Orion perfectly in orbit. The spacecraft set course for the moon and flawlessly performed a crucial 20-minute engine burn. The engines stayed true throughout the flight, firing multiple times to slip into and out of lunar orbit and then return home. Along the way, the mission managers didn’t discover any major anomalies on board, just a series of small occurrences that they dubbed “funnies” – things that were unexpected but not really problematic.

“The surprises we’re getting are pleasant surprises,” said Mike Sarafin, NASA’s Artemis mission manager, during a press conference ahead of the Nov. 30 splashdown. and it meets or exceeds expectations across the board.”

Perhaps the most serious problem during the mission occurred on the ground during the first weekend in December, when the Goldstone radio telescope, the backbone of NASA’s Deep Space Network, went offline, preventing communications with the spacecraft for several hours. The launch facility at Kennedy Space Center also suffered some unexpected damage when the SLS jumped off the launch pad, with shock waves and plumes of exhaust gas hitting the mobile launch structure and blasting the elevator doors.

In fact, things went so smoothly that as the mission progressed, managers felt confident enough to conduct additional on-the-fly tests of the spacecraft’s capabilities. And in the end everything worked.

“We get exactly what we needed, which is a test drive of the systems to make sure they all work,” says Dumbacher. “The fact that it’s working so well tells us that we have a system that is ready to go, and I suspect they will conclude that it will be safe to put people on the next system.”

Problematic payloads

Though Artemis I achieved its primary goals — to demonstrate Orion’s ability in space and successfully return the starship to Earth — some of the mission’s lower-priority ancillary tasks produced decidedly mixed results. As the spacecraft shot into orbit, it was carrying 10 CubeSats, or shoebox-sized science experiments. Some of these aimed at the moon to study ice and other features on its surface. Others were sent to monitor the space environment. One, NASA’s NEA Scout, was even targeted for a rendezvous with a near-Earth asteroid.

Of those 10 CubeSats, about half worked as planned. It’s not clear if the problems with the others are related to the experiments’ long stay on board the rocket – they were loaded onto the SLS more than a year ago and some were deployed without fully charged batteries – or the challenge of a small one to design satellite to work in space.

NEA Scout is considered missing and has yet to make ground contact; His team doesn’t even know if the spacecraft was ever powered on. A Japanese CubeSat, OMOTENASHI, was supposed to send a small lander to the lunar surface, but went out of control after the deployment, preventing further operations. LunaH-Map, another NASA CubeSat, failed to complete a crucial propulsion maneuver and is now unable to fulfill its goal of mapping ice deposits around the moon’s south pole.

“They’re all going into space, which isn’t a traditional environment for CubeSats — it’s more of a challenge,” says Paulo Lozano of the Massachusetts Institute of Technology, who builds propulsion systems for small satellites. Lozano says he’s really impressed with the CubeSats’ overall performance, calling the missions that are struggling the most “ambitious.”

“There aren’t that many opportunities to actually go into space with CubeSats, so having more of those opportunities available — I think it’s a great thing for small satellites,” says Lozano. “I think there’s going to be a lot of things to learn about how to design these spacecraft so that in the future we can design small spacecraft that can do what big spacecraft can do.”

“Earthrise”, again

Despite this hiccup, Artemis I fared much better than its equivalent mission during the Apollo program: Apollo 6 in 1968, the last unmanned test flight of the Saturn V rocket and Apollo spacecraft, which nearly failed.

“She has not fulfilled her mission profile. There were big problems with [engine] vibrations at startup. They had engine failures – the engines died out early. It was unable to fly to the moon; it had to stay in Earth orbit,” says Muir-Harmony. “Those were pretty important issues that came up on this mission. But they got data. You could analyze the mission. They felt like they could move on to the next mission.”

Even as Apollo 6 hobbled across the finish line, NASA chose to put humans aboard Apollo 7, who orbited the Earth for 10 days and set the stage for subsequent missions that took astronauts to lunar orbit and then to the lunar surface.

“I’d be surprised — if this mission went like Apollo 6 — if we didn’t do another test mission, but that’s hard to say,” says Muir-Harmony. “We now have many more decades of space experience. This is a very different situation than in the 1960s, when we had little space experience.”

Perhaps it is fitting that exactly half a century to the day after Apollo 17 landed in a mountain range on the southeastern edge of the lunar region of Mare Serenitatis, Orion returned to Earth in the same manner as the water masses of yore. Before the Apollo 17 crew reached the Moon, they captured an image of Earth — a swirling, sandy-blue marble shimmering against inky nothingness — that has become one of the most recognizable depictions of our planet. Orion also captured cosmic views during his journey and sent home a stream of beautiful images. In a serieswhile Orion circles the bend of the moon and is visible in the foreground, a crescent of Earth shimmers above the monochromatic lunar horizon – a homage to Apollo 8’s “Earthrise” for the Artemis generation.

December 14 marks the 50th anniversary of Apollo 17’s departure from the surface – when NASA astronaut Eugene Cernan became the last human to set foot on the moon, after towing several hundred pounds of lunar rock into his spacecraft. Although Cernan knew when he left that the moon would return to uninhabited, desolate solitude, he could not have foreseen at the time that it would be decades before humans returned.

“I’m on the surface. And as I take man’s last step off the surface, back home for some time – but we don’t think too far in the future – I just want to [say] what I think history will record,” Cernan said, “that America’s challenge today forged the fate of humanity tomorrow.”