NASA’s Artemis 1 mission concluded with Orion’s immaculate splashdown in the Pacific Ocean on Sunday. Seemingly a billion years—and most assuredly a few billion dollars—in the making, the mission ended far too quickly for space junkies like me. But in those short few weeks, it managed to nail all its primary objectives. Artemis 1 was strictly meant as a demonstration mission, a way for NASA to test its new SLS megarocket and Orion spacecraft.

It’s still early days, but the mission appears to have been a big success. And because NASA achieved its major goals, we can talk about what went right, what went wrong, and what the successful mission means for the future. Here are seven things we learned from Artemis 1.

1. NASA’s Artemis Moon plans are officially on track

For years, I’ve had to write about NASA’s “upcoming Artemis missions” or “pending trips to the Moon,” but with the success of Artemis 1, it’s fair to say that the space agency’s next era of exploration has officially begun. Artemis—we are officially in you.

I have little doubt that NASA’s current timelines for the Artemis missions, including a crewed landing in 2025, are wholly unrealistic. The space agency’s auditor general has said as much. Anticipated launch dates will repeatedly be pushed back for various reasons, whether it be on account of overdue Moonsuits, lunar landers, or any other element required for these increasingly complex missions.

It’s doubtful that Congress will sabotage or otherwise scuttle NASA’s Artemis plans by withholding funds, but as the holder of the purse strings, it remains the chamber’s prerogative to do so. That said, China is full steam ahead on its plans to send its taikonauts to the lunar surface during the mid-2030s. The U.S. has already put humans on the Moon, but China’s space ambitions are spawning a renewed space race, with some experts saying “we’re falling behind.”

2. SLS is a beast

NASA’s Space Launch System rocket finally roared to life on November 16, sending an uncrewed Orion on its historic journey around the Moon. Blasting off with 8.8 million pounds of thrust, it’s now the most powerful operational rocket in the world and the most powerful rocket ever built. The space agency finally has its megarocket, a necessity of the Artemis program, which seeks to land humans on the Moon later this decade and place a space station, called Gateway, in lunar orbit.

“The first launch of the Space Launch System rocket was simply eye-watering,” Mark Sarafin, Artemis mission manager, said in a November 30 statement, adding that the rocket’s performance “was off by less than 0.3 percent in all cases across the board.” The rocket program was marred by budget overruns and delays, but SLS ultimately did exactly what it was supposed to do—while dropping our jaws in the process.

3. SLS wreaks havoc to the launch pad—and the pocket books

SLS is awesome, no doubt, but it comes with certain complications.

The launch vehicle’s core stage runs on a mixture of liquid oxygen and liquid hydrogen, the same super-leaky propellant that caused major headaches during the Space Shuttle era. Kennedy Space Center ground teams battled hydrogen leaks in advance of the rocket’s inaugural launch, resulting in multiple scrubs and an impromptu cryogenic tanking test in September. The team learned that the finicky rocket requires a kinder, gentler approach to tanking, but hydrogen leaks may continue to pose a problem during future launches.

When the megarocket did finally manage to blast off, it caused significant damage at the launch pad, including new scorch marks, missing paint, battered nitrogen and helium supply lines, and fried cameras. At liftoff, the powerful shockwave also tore off the tower’s elevator doors. NASA officials downplayed the damage, saying some of it was expected. Regardless, the mobile launcher is now in the Vehicle Assembly Building undergoing repairs.

Finally, the rocket, which first emerged as an idea 12 years ago and cost $23 billion to develop, is fully expendable, meaning each SLS rocket must be built from scratch. NASA inspector general Paul Martin expects each launch of SLS to cost upwards of $4.1 billion, “a price tag that strikes us as unsustainable,” he told Congress earlier this year.

SpaceX is currently building its own megarocket, called Starship, which promises to be fully reusable and more powerful than SLS (though to be clear, and as NASA administrator Bill Nelson has stated on numerous occasions, the space agency has no intention of launching Orion with Starship). NASA’s rocket will become an anachronism the moment that Elon Musk’s rocket takes flight. So while SLS’s debut performance was exemplary, the Artemis program as a whole is far from ideal in terms of its execution.

4. Deep space is unwelcoming place for cubesats

SLS, in addition to Orion, delivered 10 cubesats to space. These secondary Artemis 1 payloads went off on their various journeys, but only six of them are functioning as intended, including Arizona State University’s LunaH-Map mission, NASA’s BioSentinel, and Japan’s EQUULEUS mission.

The same cannot be said for the other four, namely Southwest Research Institute’s CuSP (CubeSat for Solar Particles), Lockheed Martin’s LunIR, NASA’s Near-Earth Asteroid Scout (NEA Scout), and Japan’s tiny OMOTENASHI lunar lander—all of which failed shortly after launch. Each failed for different reasons, such as the inability to establish deep space communications, issues with battery power, and deficient designs. The high attrition rate served as a potent reminder: Space is hard, and deep space is even harder.

5. Orion is humanity’s most impressive spaceship yet

We’ve witnessed plenty of capable spacecraft over the years. NASA’s Apollo Command and Service Module was really cool, as was the Space Shuttle. Russia’s Soyuz continues to be super reliable, while SpaceX’s Crew Dragon is the epitome of modern spacefaring. These spaceships are all great, but NASA’s Orion is now, in my opinion, the most impressive crew-friendly vehicle ever built.

The partially reusable Orion consists of a crew module, designed by Lockheed Martin, and the expendable European Service Module, built by Airbus Defence and Space. The system performed exceptionally well during the entire Artemis 1 mission, save for some minor annoyances (which I’ll get to in just a bit). Orion traveled to the Moon, successfully entered into its target distant retrograde orbit, performed a pair of close lunar flybys, and managed to survive skip reentry and splashdown. Each and every course correction maneuver was pulled off without difficulty, with Orion using less fuel than expected.

More on this story: NASA Wants More Spacecraft for Its Upcoming Artemis Moon Missions

The uncrewed Orion clocked over 1.3 million miles during its journey, while establishing a pair of new milestone records. The spacecraft flew to a maximum distance of 268,554 miles (432,194 kilometers) from Earth—the farthest distance traveled by any crew-rated vehicle. And when it came home, Orion slammed into the atmosphere at speeds reaching Mach 32, marking the fastest return velocity in history for a passenger spacecraft. The capsule’s 16.5-foot-wide heat shield protected Orion from the 5,000-degree-Fahrenheit temperatures experienced during reentry.

The next big test for Orion will be Artemis 2, for which it will need to transport four astronauts around the Moon and back. But the upcoming Artemis missions are only the beginning, as NASA plans to use Orion for crewed trips to Mars one day.

6. Orion still needs some tweaking

Artemis 1 unfolded as planned, but that’s not to say it wasn’t without problems. Mike Sarafin, the mission manager, called these anomalies “funnies” throughout Orion’s journey, but I doubt the team found them very amusing.

During the early days of the mission, Orion’s star tracker, which assists with navigation, was “dazzled” by Orion’s thruster plumes. “The thrusters were being picked up by the star tracker because it was thrusting over the field of view of the star tracker by design,” Sarafin told reporters on November 18. “The light was hitting the plume and it was picking it up,” which confused the software. Ultimately, nothing was really wrong with the star tracker, and the team was able to move forward once the problem was recognized.

The scariest moment happened on November 23, the seventh day of the mission, when ground controllers temporarily and unexpectedly lost contact with the spacecraft for 47 minutes. NASA isn’t sure what caused the issue.

During the final days of the mission, one of Orion’s four limiters suddenly switched off. This limiter, which is responsible for downstream power, was successfully turned back on before the glitch was able to cause serious problems. The anomaly might be related to a similar issue experienced earlier, when a component in the service module spontaneously opened without a command. Seems as though Orion brought a gremlin along for the journey.

Lastly, one of Orion’s phased array antennas exhibited “degraded behavior” during the final days of the mission, as Sarfin told reporters on December 8. This resulted in “low performance” and some “communication problems,” but nothing that endangered the mission, he said. This issue, among others, will be scrutinized and hopefully addressed in time for Artemis 2, currently planned for 2024.

7. The Moon remains a desolate and beautiful place

Images beamed back from the lunar environment served as a reminder that the Moon, though dim and stark, remains an intriguing and visually fascinating place. Sure, the Apollo missions brought back unprecedented images of the lunar landscape, but it’s still the Moon—our Moon—a place we don’t tend to visit very often (with all due respect to NASA’s Lunar Reconnaissance Orbiter, in operation since 2009, and China’s Chang’e 4 lander Yutu-2 rover, which reached the far side in early 2019).

Artemis 1 was like visiting an old friend, though an old friend filled with craters, mountain ranges, and an assortment of other fascinating surface features. What’s more, the lunar environment is a place where we can expect the unexpected, including impossibly picturesque Earthrises illuminated by the Sun. So yes, the Moon remains a worthwhile destination, as we set our sights on the next exciting phase of human space exploration.

More: See the Best Images from the Thrilling Artemis 1 Splashdown