After flying around the moon, NASA’s Orion spacecraft is scheduled to touch down on Sunday

The Orion spacecraft swung by the moon on Monday, flying within 130 km of that world’s surface as it returned to Earth this weekend.

In making this “powered flyby” to move away from the Moon, the Orion Service Module performed the longest main engine firing ever, lasting 3 minutes and 27 seconds. Following the successful completion of the maneuver, NASA’s mission management team gave the go-ahead to send recovery teams to the Pacific Ocean, where Orion is scheduled to land on Sunday, mid-day.

By orbiting the Moon and returning from it during its deep space mission, Orion has already completed four main thrust burns. This concludes a major test of the spacecraft and its Propulsion Service Module, which was built by the European Space Agency. Although a prototype version of Orion made a flight 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 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 landing portion of the mission remaining. The spacecraft’s heat shield must demonstrate its ability to survive re-entry at 39,400 km/h. That big test will come Sunday during a fiery re-entry into Earth’s atmosphere.

Slight problem with the power supply

So far, Orion’s test flight is going remarkably well. Usually new spacecraft have problems with thrusters, navigation, on-board avionics, etc. However, Orion has not had any serious problems. The only real troubleshooting involved a problem with the car’s power systems.

The problem occurred with four “locking current limiters” that help direct power to Orion’s propulsion and heating systems. For some reason, Orion’s automated controllers commanded the four current limiters to “open” when no such command should have been sent. “We’re not quite sure of the root cause of the problem, but teams are doing tests on the ground,” Debbie Court, deputy manager of the Orion program, said during a briefing Monday night at the Johnson Space Center in Houston.

This system is somewhat like a circuit breaker box in the home, and for some reason four of the circuit breakers were open when they shouldn’t have been. This posed no threat to Orion as it has backup power systems. If there was a crew on board, a small procedure would be needed to explain the problem.

In an interview after the news briefing, Cort said he did not think the problem would affect the service module that will be used for the Artemis II mission. This hardware has already been built and is being tested in the United States.

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