Crew members aboard NASA’s Orion spacecraft have returned to Earth — the final phase of a mission that officials say is as critical as launch.

After their trip around the moon, crews prepared the spacecraft for reentry. A splashdown came just after 7 p.m. Central Time Friday off the coast of San Diego in perfect weather conditions.

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NASA officials emphasized that reentry carries significant risks.

“Every engineer, every technician that’s touched this machine — tomorrow belongs to you,” said Amit Kshatriya, a NASA associate administrator the day before splashdown. “The crew has done their part. Now we have to do ours.”

Inside NASA’s mission evaluation room in Houston, teams of engineers tracked every system on the spacecraft. Orion program manager Howard Hu said the group is responsible for identifying and resolving any issues that arise during flight.

“When there’s anything going on, it’s this engineering team that is responsible for deducing what the issues are and helping the flight control team recover the system,” Hu said.

The spacecraft was designed with redundancy in mind, meaning most systems have backups — and in some cases, multiple backups — to ensure crew safety.

Engineers reported only minor issues during the mission, including a problem with the spacecraft’s toilet and a couple of faulty valves. None were considered serious.

“We will fix what we need to fix for future missions,” Hu said.

Work on those future missions is already underway as part of NASA’s Artemis program, which aims to return humans to the Moon. Officials say later missions, including Artemis V, are intended to build toward sustained lunar exploration.

“For me, it is about landing people on the moon,” Hu said. “We are the transportation. It feels great that we’re operating the spaceship, getting people to the lunar vicinity. Now, once we establish that transportation, I want to see astronauts get on the lander, do the science they need to do, back into Orion and get them back home.”