Illustration of NASA’s Orion spacecraft flying through space. Credit: NASA
NASA Artemis I – Flight Day 19: Orion Prepares for Close Lunar Flyby, Teams Examine Power Conditioning Problem
On the 19th flight day of the Artemis I mission, Orion performed the second return trajectory correction burn on Sunday, December 4 at 10:43 a.m. CST, using the auxiliary thrusters and increasing the spacecraft’s speed by 1.16 mph (1.71 feet per second).
Orion experienced a problem with a power conditioning distribution unit (PCDU) shortly after acquiring the signal with the Deep Space Network’s Canberra ground station at 12:41 am CST. Specifically, the problem was that four of the blocking current limiters responsible for the downstream feed suddenly shut down. These lower-level switches connect to the propulsion and heater subsystems. After crews confirmed the system was healthy, they successfully re-energized downstream components. There was no disruption of power to any critical systems, and there were no adverse effects on Orion’s navigation or communication systems.
The teams are examining whether a possible contributor to this problem is related to a power configuration test implemented by flight crews to investigate previous cases where one of the eight umbilical lock current limiting units opened without any order The umbilical closed successfully each time and there was no loss of power flowing to the spacecraft avionics.
On the 19th day of the Artemis I mission, Orion captures Earth from a camera mounted on one of its solar arrays as the spacecraft prepares for its return flyby of the Moon on December 5, when it will pass approximately 127 km (79 miles). above the lunar surface. Credit: NASA
The spacecraft obtained additional data using its optical navigation system, which is a sensitive camera for taking images of the Moon and Earth to help orient the spacecraft by observing the size and position of celestial bodies in the images. Engineers also continue to work on plans to accomplish several additional test objectives during Orion’s journey back to Earth. A series of test targets provide engineers with insight into how Orion operates in space, allowing them opportunities to validate performance models and learn as much as possible about the spacecraft.
In preparation for Orion’s return to Earth, the team from NASA’s Exploration Earth Systems Program and the US Navy, which will retrieve Orion from the Pacific Ocean, completed its final day of training at sea, using a simulated capsule in the water for divers and small boats. to practice open water recovery procedures.
On Monday, December 5, Orion will make its closest approach to the Moon, flying 79.2 miles above the lunar surface. It will make the return flight at 10:43 a.m. CST, which will last about 3 minutes and 27 seconds, changing the spacecraft’s speed by about 655 mph (961 feet per second) or 1,054 km/h (293 meters per second) . second). The return powered flyby is the last major maneuver of the mission, with only smaller trajectory corrections to target Earth.
Live coverage of the upcoming lunar flyby and burn will begin at 8 a.m. CST on NASA TV, the agency’s website and the NASA app. During the coverage, the lighting will be different than it was during Orion’s close lunar flyby on November 21. The spacecraft will lose communications with Earth for approximately 31 minutes beginning at 10:40 a.m. CST as it flies behind the far side of the Moon. .
At 4:00 p.m. CST on December 5, NASA leaders will discuss the results of the re-entry flyby burn and the deployment of recovery assets at sea ahead of the Orion dump on December 11 december Live coverage will be available on all NASA channels.
Shortly after 4:30 pm CST on December 4, Orion was traveling 222,213 miles (357,617 km) from Earth and 23,873 miles (38,420 km) from the Moon, cruising at 3,076 mph (4,950 km/h).