After the lunar flyby, NASA’s Orion spacecraft is scheduled to splash down on Sunday

The Orion spacecraft swung by the moon on Monday and flew within 130 km of that world’s surface as it set course to return to Earth this weekend.

In making this “powered flyby” away from the Moon, the Orion Service Module had its longest main engine burn to date, lasting 3 minutes and 27 seconds. After successfully completing the maneuver, NASA’s mission management team took the step to send recovery teams to the Pacific Ocean, where Orion is due to dock on Sunday, midway through day.

By orbiting the Moon and exiting it again during its deep space mission, Orion has now completed four main propellant burns. This completes a major test of the spacecraft and its propulsion service module, which was built by the European Space Agency. Although a normal version of Orion did fly in 2014, it did so without a service module.

As part of this Artemis I mission, NASA is now three weeks into a 25.5-day test flight of the Orion spacecraft. The goal is to validate the spacecraft’s capabilities before a human flight of the vehicle in about two years, the Artemis II mission.

Orion has accomplished most of its primary objectives so far, with only the entry, descent and part of its mission ahead. The spacecraft’s heat shield must demonstrate its ability to survive re-entry at a speed of 39,400 km/h. That big test will come Sunday during a fiery re-entry into Earth’s atmosphere.

A minor power issue

So far, Orion’s test flight has gone remarkably well. Usually with new spacecraft there are problems with the thrusters, navigation or avionics on board and more. However, Orion has not had any major problems. The only real troubleshooting has involved a problem with the vehicle’s power systems.

The problem occurred with four “blocking current limiters” that help direct power to the propulsion and heating systems on Orion. For some reason, Orion’s automated controllers commanded all four current limiters to “open” when this command was not supposed to be sent. “We’re not exactly sure what the root cause of the problem is, but teams are doing field tests,” Debbie Korth, deputy manager of the Orion Program, said during a briefing Monday evening at the Johnson Space Center in Houston.

This system is a bit like a switch box in a home, and for some reason four of the switches opened when they weren’t supposed to. This did not pose a threat to Orion as there are backup power systems. If there was a crew on board, it would have required a minor procedure to explain the problem.

In an interview after the news conference, Korth said he did not think the failure would have an impact on the service module that will be used for the Artemis II mission. This hardware is already built and being tested in the United States.

“I think it’s probably too early to say for sure, but ideally we won’t want to disrupt the Artemis II service module,” he said. “That might be something we can handle with software.”